Biblioteca para criação simples e rápida de programas para MetaTrader (Parte XVI): eventos de coleção de símbolos

22 novembro 2019, 12:53
Artyom Trishkin
0
969

Sumário

Anteriormente, ao criar um objeto de conta e uma coleção de contas na parte 12 e, em seguida, ao rastrear os eventos da conta atual na parte 13 da descrição da biblioteca, nós sozinhos definimos um novo tipo de objetos para a biblioteca que enviam seus eventos para o objeto base Engine.


Os princípios de rastreamento de eventos da conta são diferentes dos princípios de rastreamento de eventos de negociação, que consideramos no artigo 4: os eventos de negociação são determinados e inseridos na coleção de eventos de negociação para acessar qualquer um dos eventos ocorridos anteriormente, já os eventos da conta funcionam em tempo real, "aqui e agora": o evento é determinado e enviado através de EventChartCustom() para o gráfico contendo o programa e para o objeto base da biblioteca. Em seguida, no objeto base da biblioteca, no programa pode-se acessar a lista de eventos ocorridos simultaneamente e processá-los. É assim que os eventos são organizados no objeto de conta.

E da mesma forma, organizamos os eventos na coleção de objetos-símbolos. A diferença está apenas na quantidade - rastreamos os eventos da conta apenas para a conta atual à qual atualmente temos uma conexão, já os eventos de símbolos precisam ser rastreados para cada coleção - quer apenas um símbolo atual, dois, três ou todos disponíveis no servidor.

Aqui compreendemos que quase todos os objetos são dotados de uma certa quantidade de propriedades que se repetem de objeto para objeto. Além disso, escrevemos cada uma dessas propriedades repetidamente em cada novo objeto durante seu desenvolvimento.

Isso faz com que inequivocamente decidamos criar um objeto base a partir do qual serão herdados todos os objetos da biblioteca. Agora eles são herdados do objeto base CObject da biblioteca padrão. Nós criaremos mais um objeto herdeiro da CObject e herdaremos dele todos os objetos de nossa biblioteca. Assim, todas as propriedades comuns para cada um dos objetos poderão ser registradas uma vez no objeto base, e todos os objetos herdeiros serão automaticamente dotados destas propriedades.

Mas o mais interessante é que agora podemos criar o objeto-evento e registrá-lo no objeto base, e todos os nossos objetos da biblioteca serão dotados com a possibilidade de enviar seus eventos para o programa. É disso que precisamos no conceito de biblioteca — para que os objetos possam sozinhos notificar o programa sobre seus status, enquanto a biblioteca/programa, desse modo, possa processá-los, tomar uma decisão (programa) ou executar as ações necessárias para processamento de eventos de objetos (biblioteca). Assim, aumentando a interatividade da própria biblioteca e simplificando bastante o desenvolvimento de programas para o usuário final, pois a biblioteca assume todas as ações para processar os eventos de qualquer objeto.

A estrutura do objeto do evento repetirá os dados necessários para o envio através da função EventChartCustom() — ID de evento, parâmetro long, parâmetro double e parâmetro de string do evento. Assim, é mais fácil enviar eventos ao programa, pois ao registrar um evento de objeto, todos os dados que precisam ser enviados ao programa sobre o evento acontecido são preenchidos imediatamente na classe do objeto em que ele ocorre, e precisamos apenas obtê-lo e redirecioná-lo para o programa para processamento adicional.

Terminemos com a teoria e continuemos com o desenvolvimento. Primeiro, criamos um objeto-evento, depois um objeto base e, finalmente, escrevemos o rastreamento de eventos da coleção de símbolos e corrigimos a classe de evento da conta com base no conceito criado. Não mudaremos os eventos de negociação — eles têm uma estrutura completamente diferente e não se encaixam neste conceito. Além disso, eles já têm uma aparência completa, trabalham e enviam seus dados para o programa.

Classe de objeto base para todos os objetos de biblioteca

No diretório da biblioteca \MQL5\Include\DoEasy\Objects\, criamos a nova classe CBaseObj no arquivo BaseObj.mqh. O objeto base da classe deve ser o objeto base da biblioteca padrão CObject. A classe será pequena, por isso, darei sua lista completa e, em seguida, vamos analisá-la por membros e métodos.

Observação: a fim de não criar um novo arquivo para a classe de evento de objetos, escrevemos esta classe antes da classe base de objetos diretamente no mesmo arquivo:
//+------------------------------------------------------------------+
//|                                                      BaseObj.mqh |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
#property strict    // Necessary for mql4
//+------------------------------------------------------------------+
//| Include files                                                    |
//+------------------------------------------------------------------+
#include <Arrays\ArrayObj.mqh>
#include "..\Services\DELib.mqh"
//+------------------------------------------------------------------+
//| Base object event class for all library objects                  |
//+------------------------------------------------------------------+
class CEventBaseObj : public CObject
  {
private:
   long              m_time;
   long              m_chart_id;
   ushort            m_event_id;
   long              m_lparam;
   double            m_dparam;
   string            m_sparam;
public:
   void              Time(const long time)               { this.m_time=time;           }
   long              Time(void)                    const { return this.m_time;         }
   void              ChartID(const long chart_id)        { this.m_chart_id=chart_id;   }
   long              ChartID(void)                 const { return this.m_chart_id;     }
   void              ID(const ushort id)                 { this.m_event_id=id;         }
   ushort            ID(void)                      const { return this.m_event_id;     }
   void              LParam(const long lparam)           { this.m_lparam=lparam;       }
   long              LParam(void)                  const { return this.m_lparam;       }
   void              DParam(const double dparam)         { this.m_dparam=dparam;       }
   double            DParam(void)                  const { return this.m_dparam;       }
   void              SParam(const string sparam)         { this.m_sparam=sparam;       }
   string            SParam(void)                  const { return this.m_sparam;       }
public:
//--- Constructor
                     CEventBaseObj(const ushort event_id,const long lparam,const double dparam,const string sparam) : m_chart_id(::ChartID()) 
                       { 
                        this.m_event_id=event_id;
                        this.m_lparam=lparam;
                        this.m_dparam=dparam;
                        this.m_sparam=sparam;
                       }
//--- Comparison method to search for identical event objects
   virtual int       Compare(const CObject *node,const int mode=0) const 
                       {   
                        const CEventBaseObj *compared=node;
                        return
                          (
                           this.ID()>compared.ID()          ?  1  :
                           this.ID()<compared.ID()          ? -1  :
                           this.LParam()>compared.LParam()  ?  1  :
                           this.LParam()<compared.LParam()  ? -1  :
                           this.DParam()>compared.DParam()  ?  1  :
                           this.DParam()<compared.DParam()  ? -1  :
                           this.SParam()>compared.SParam()  ?  1  :
                           this.SParam()<compared.SParam()  ? -1  :  0
                          );
                       } 
  };
//+------------------------------------------------------------------+
//| Base object class for all library objects                        |
//+------------------------------------------------------------------+
class CBaseObj : public CObject
  {
private:

protected:
   CArrayObj         m_list_events;                            // Object event list
   MqlTick           m_tick;                                   // Tick structure for receiving quote data
   double            m_hash_sum;                               // Object data hash sum
   double            m_hash_sum_prev;                          // Object data hash sum during the previous check
   int               m_digits_currency;                        // Number of decimal places in an account currency
   int               m_global_error;                           // Global error code
   long              m_chart_id;                               // Control program chart ID
   bool              m_is_event;                               // Object event flag
   int               m_event_code;                             // Object event code
   string            m_name;                                   // Object name
   string            m_folder_name;                            // Name of the folder storing CBaseObj descendant objects 

//--- Return time in milliseconds from MqlTick
   long              TickTime(void)                            const { return #ifdef __MQL5__ this.m_tick.time_msc #else this.m_tick.time*1000 #endif ;}
//--- return the flag of the event code presence in the event object
   bool              IsPresentEventFlag(const int change_code) const { return (this.m_event_code & change_code)==change_code; }
//--- Return the number of decimal places of the account currency
   int               DigitsCurrency(void)                      const { return this.m_digits_currency; }
//--- Returns the number of decimal places in the 'double' value
   int               GetDigits(const double value)             const;
//--- Initialize the variables of (1) tracked, (2) controlled object data (implementation in the descendants)
   virtual void      InitChangesParams(void);
   virtual void      InitControlsParams(void);
//--- (1) Check the object change, return the change code, (2) set the event type and fill in the list of events (implementation in the descendants)
   virtual int       SetEventCode(void);
   virtual void      SetTypeEvent(void);
public:
//--- Add the event object to the list
   bool              EventAdd(const ushort event_id,const long lparam,const double dparam,const string sparam);
//--- Return the occurred event flag to the object data
   bool              IsEvent(void)                             const { return this.m_is_event;              }
//--- Return (1) the list of events, (2) the object event code and (3) the global error code
   CArrayObj        *GetListEvents(void)                             { return &this.m_list_events;          }
   int               GetEventCode(void)                        const { return this.m_event_code;            }
   int               GetError(void)                            const { return this.m_global_error;          }
//--- Return the event object by its number in the list
   CEventBaseObj    *GetEvent(const int shift=WRONG_VALUE,const bool check_out=true);
//--- Return the number of object events
   int               GetEventsTotal(void)                      const { return this.m_list_events.Total();   }
//--- (1) Set and (2) return the chart ID of the control program
   void              SetChartID(const long id)                       { this.m_chart_id=id;                  }
   long              GetChartID(void)                          const { return this.m_chart_id;              }
//--- (1) Set the sub-folder name, (2) return the folder name for storing descendant object files
   void              SetSubFolderName(const string name)             { this.m_folder_name=DIRECTORY+name;   }
   string            GetFolderName(void)                       const { return this.m_folder_name;           }
//--- Return the object name
   string            GetName(void)                             const { return this.m_name;                  }
//--- Update the object data (implementation in the descendants)
   virtual void      Refresh(void);
   
//--- Constructor
                     CBaseObj();
  };
//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CBaseObj::CBaseObj() : m_global_error(ERR_SUCCESS),
                       m_hash_sum(0),m_hash_sum_prev(0),
                       m_is_event(false),m_event_code(0),
                       m_chart_id(::ChartID()),
                       m_folder_name(DIRECTORY),
                       m_name("")
  {
   ::ZeroMemory(this.m_tick);
   this.m_digits_currency=(#ifdef __MQL5__ (int)::AccountInfoInteger(ACCOUNT_CURRENCY_DIGITS) #else 2 #endif);
   this.m_list_events.Clear();
   this.m_list_events.Sort();
  }
//+------------------------------------------------------------------+
//| Add the event object to the list                                 |
//+------------------------------------------------------------------+
bool CBaseObj::EventAdd(const ushort event_id,const long lparam,const double dparam,const string sparam)
  {
   CEventBaseObj *event=new CEventBaseObj(event_id,lparam,dparam,sparam);
   if(event==NULL)
      return false;
   this.m_list_events.Sort();
   if(this.m_list_events.Search(event)>WRONG_VALUE)
     {
      delete event;
      return false;
     }
   return this.m_list_events.Add(event);
  }
//+------------------------------------------------------------------+
//| Return the object event by its index in the list                 |
//+------------------------------------------------------------------+
CEventBaseObj *CBaseObj::GetEvent(const int shift=WRONG_VALUE,const bool check_out=true)
  {
   int total=this.m_list_events.Total();
   if(total==0 || (!check_out && shift>total-1))
      return NULL;   
   int index=(shift<=0 ? total-1 : shift>total-1 ? 0 : total-shift-1);
   CEventBaseObj *event=this.m_list_events.At(index);
   return(event!=NULL ? event : NULL);
  }
//+------------------------------------------------------------------+
//| Return the number of decimal places in the 'double' value        |
//+------------------------------------------------------------------+
int CBaseObj::GetDigits(const double value) const
  {
   string val_str=(string)value;
   int len=::StringLen(val_str);
   int n=len-::StringFind(val_str,".",0)-1;
   if(::StringSubstr(val_str,len-1,1)=="0")
      n--;
   return n;
  }
//+------------------------------------------------------------------+

Analisemos a classe de eventos do objeto base

Na classe de eventos do objeto base na seção privada, são declaradas as variáveis-membros da classe para armazenar todas as propriedades do evento:

private:
   long              m_time;
   long              m_chart_id;
   ushort            m_event_id;
   long              m_lparam;
   double            m_dparam;
   string            m_sparam;

Hora do evento, ID do gráfico para o qual é enviado o evento, ID do evento, valor long, valor double e valor de string dos eventos que serão transmitidos para o gráfico do programa de controle.
O construtor da classe passa imediatamente os valores para a maioria destas variáveis:

//--- Constructor
                     CEventBaseObj(const ushort event_id,const long lparam,const double dparam,const string sparam) : m_chart_id(::ChartID()) 
                       { 
                        this.m_event_id=event_id;
                        this.m_lparam=lparam;
                        this.m_dparam=dparam;
                        this.m_sparam=sparam;
                       }

Aqui os valores transmitidos são atribuídos a ele.
Também na lista de inicialização de classe, à variável-indicador do gráfico é atribuído o valor ID do gráfico atual.

Método para comparar duas classes-eventos de objetos:

//--- Comparison method to search for identical event objects
   virtual int       Compare(const CObject *node,const int mode=0) const 
                       {   
                        const CEventBaseObj *compared=node;
                        return
                          (
                           this.ID()>compared.ID()           -- 1  :
                           this.ID()<compared.ID()          ? -1  :
                           this.LParam()>compared.LParam()   -- 1  :
                           this.LParam()<compared.LParam()  ? -1  :
                           this.DParam()>compared.DParam()   -- 1  :
                           this.DParam()<compared.DParam()  ? -1  :
                           this.SParam()>compared.SParam()   -- 1  :
                           this.SParam()<compared.SParam()  ? -1  :  0  
                          );
                       } 

Compara - por elementos - todos os campos de duas classes — a atual e a transferida para o método de acordo com o ponteiro. Se todos os campos forem iguais, o método retornará 0, que é necessário para encontrar exatamente o mesmo objeto na lista dinâmica de ponteiros da biblioteca padrão — afinal, esses objetos são armazenados na lista CArrayObj, enquanto seu método Search() é projetado para procurar objetos idênticos na lista:

//+------------------------------------------------------------------+
//| Search of position of element in a sorted array                  |
//+------------------------------------------------------------------+
int CArrayObj::Search(const CObject *element) const
  {
   int pos;
//--- check
   if(m_data_total==0 || !CheckPointer(element) || m_sort_mode==-1)
      return(-1);
//--- search
   pos=QuickSearch(element);
   if(m_data[pos].Compare(element,m_sort_mode)==0)
      return(pos);
//--- not found
   return(-1);
  }
//+------------------------------------------------------------------+

O objeto deve ter o método virtual Compare(), que retorna 0 se todas as propriedades dos dois objetos coincidirem)

Na seção pública da classe são declarados os métodos para definir e retornar todas as propriedades do objeto:

public:
   void              Time(const long time)               { this.m_time=time;           }
   long              Time(void)                    const { return this.m_time;         }
   void              ChartID(const long chart_id)        { this.m_chart_id=chart_id;   }
   long              ChartID(void)                 const { return this.m_chart_id;     }
   void              ID(const ushort id)                 { this.m_event_id=id;         }
   ushort            ID(void)                      const { return this.m_event_id;     }
   void              LParam(const long lparam)           { this.m_lparam=lparam;       }
   long              LParam(void)                  const { return this.m_lparam;       }
   void              DParam(const double dparam)         { this.m_dparam=dparam;       }
   double            DParam(void)                  const { return this.m_dparam;       }
   void              SParam(const string sparam)         { this.m_sparam=sparam;       }
   string            SParam(void)                  const { return this.m_sparam;       }

Aqui se consegue ver tudo mais claramente, portanto não são necessários comentários. Esta é toda a classe de eventos de objetos.

Consideremos a classe de objeto base para todos os objetos da biblioteca.

Na seção protegida da classe, são declaradas as variáveis-membros da classe que já conhecemos graças aos objetos anteriores:

protected:
   CArrayObj         m_list_events;                            // Object event list
   MqlTick           m_tick;                                   // Tick structure for receiving quote data
   double            m_hash_sum;                               // Object data hash sum
   double            m_hash_sum_prev;                          // Object data hash sum during the previous check
   int               m_digits_currency;                        // Number of decimal places in an account currency
   int               m_global_error;                           // Global error code
   long              m_chart_id;                               // Control program chart ID
   bool              m_is_event;                               // Object event flag
   int               m_event_code;                             // Object event code
   string            m_name;                                   // Object name
   string            m_folder_name;                            // Name of the folder storing CBaseObj descendant objects 

  • Na lista de eventos do objeto m_list_events vamos colocar os objetos da classe de eventos, que consideramos acima. No objeto podem simultaneamente acontecer vários eventos, por isso, precisamos determiná-los todos e colocá-los nesta lista. Além disso, a partir do objeto principal da biblioteca CEngine, podemos extrair a lista de todos os eventos e processá-la.
  • A estrutura de ticks m_tick serve para obter os preços e a hora do evento.
  • A soma hash m_hash_sum é necessária para determinar as alterações que ocorreram nas propriedades do objeto.
    A alteração das propriedades do objeto é determinada comparando a soma hash ( m_hash_sum_prev) anterior e atual.
  • Número de casas decimais para a moeda da conta m_digits_currency é necessário para exibir corretamente informações sobre alguns eventos relacionados a alterações em valores monetários.
  • No código de erro global m_global_error , é registrado o número do erro recebido durante o retorno incorreto de qualquer função. Esse código é passado para o programa de chamada para processamento adicional.
  • ID do gráfico do programa de controle m_chart_id serve para indicar para qual gráfico enviar o evento que ocorreu no objeto.
  • Sinalizador de evento de objeto m_is_event é necessário indicar ao programa o evento no objeto interrogado para uma reação oportuna ao evento.
  • Código de evento de objeto m_event_code armazena os sinalizadores de todos os eventos que ocorreram simultaneamente e, pela presença desses sinalizadores, determinamos a lista de eventos de objetos que ocorreram simultaneamente.
  • O nome do objeto m_name é necessário para indicar ao programa algumas propriedades de texto do objeto do qual serão recebidos os eventos. Por exemplo, para uma conta, ele é o número da conta + nome do cliente + nome do servidor, já para um símbolo é o nome do símbolo.
  • O nome da pasta para armazenar arquivos de objetos m_folder_name é necessário para salvar o objeto num arquivo: aqui é armazenado o nome da subpasta, no qual são armazenados os arquivos de objetos do mesmo tipo.
    O diretório base para as subpastas é o diretório de localização de arquivos compartilhados de todos os terminais do cliente + nome da pasta da biblioteca: "DoEasy\\". Falamos sobre armazenamento de arquivos ao criar uma coleção de contas na parte 12, descrição da biblioteca.

Nós já criamos todas essas propriedades nos objetos de biblioteca e falamos sobre elas em diferentes partes da descrição da biblioteca, correspondentes aos objetos discutidos. Agora, colocamo-los numa classe — no objeto base de todos os objetos da biblioteca CBaseObj, e a definição desses membros da classe já foi removida das classes de objetos-herdeiros (para não descrever aqui, essas alterações podem ser visualizadas nos arquivos anexados ao artigo).

Consideremos os métodos localizados na seção privada da classe:

//--- Return time in milliseconds from MqlTick
   long              TickTime(void)                            const { return #ifdef __MQL5__ this.m_tick.time_msc #else this.m_tick.time*1000 #endif ;}
//--- return the flag of the event code presence in the event object
   bool              IsPresentEventFlag(const int change_code) const { return (this.m_event_code & change_code)==change_code; }
//--- Return the number of decimal places of the account currency
   int               DigitsCurrency(void)                      const { return this.m_digits_currency; }
//--- Returns the number of decimal places in the 'double' value
   int               GetDigits(const double value)             const;
//--- Initialize the variables of (1) tracked, (2) controlled object data (implementation in the descendants)
   virtual void      InitChangesParams(void);
   virtual void      InitControlsParams(void);
//--- (1) Check the object change, return the change code, (2) set the event type and fill in the list of events (implementation in the descendants)
   virtual int       SetEventCode(void);
   virtual void      SetTypeEvent(void);

  • Метод TickTime() возвращает время события в милисекундах. Para o MQL4, devido à ausência de milissegundos na estrutura, é retornado o tempo em segundos *1000
  • O método IsPresentEventFlag() retorna a presença do código de um evento específico no valor da variável m_event_code.
  • O método DigitsCurrency() retorna o número de casas decimais no valor da moeda da conta a partir da variável m_digits_currency.
  • O método GetDigits() calcula e retorna o número de casas decimais no valor double passado para ele.
  • O método virtual InitChangesParams() inicializa os parâmetros de todas as propriedades mutáveis do objeto.
  • O método virtual InitControlsParams() inicializa os parâmetros das propriedades do objeto monitorado.
  • O método virtual SetEventCode() verifica a alteração nas propriedades do objeto e retorna o código das alterações.
  • O método virtual SetTypeEvent() define o tipo de evento ocorrido com base no código do evento e coloca todos os eventos na lista de eventos do objeto.

Já desenvolvemos todos esses métodos em artigos anteriores e não voltaremos à sua re-descrição. Esclarecemos apenas que todos os métodos virtuais não fazem nada aqui e devem ser implementados nas classes herdeiras do objeto base.

Os métodos são declarados na seção pública da classe:

public:
//--- Add the event object to the list
   bool              EventAdd(const ushort event_id,const long lparam,const double dparam,const string sparam);
//--- Return the occurred event flag to the object data
   bool              IsEvent(void)                             const { return this.m_is_event;              }
//--- Return (1) the list of events, (2) the object event code and (3) the global error code
   CArrayObj        *GetListEvents(void)                             { return &this.m_list_events;          }
   int               GetEventCode(void)                        const { return this.m_event_code;            }
   int               GetError(void)                            const { return this.m_global_error;          }
//--- Return the event object by its number in the list
   CEventBaseObj    *GetEvent(const int shift=WRONG_VALUE,const bool check_out=true);
//--- Return the number of object events
   int               GetEventsTotal(void)                      const { return this.m_list_events.Total();   }
//--- (1) Set and (2) return the chart ID of the control program
   void              SetChartID(const long id)                       { this.m_chart_id=id;                  }
   long              GetChartID(void)                          const { return this.m_chart_id;              }
//--- (1) Set the sub-folder name, (2) return the folder name for storing descendant object files
   void              SetSubFolderName(const string name)             { this.m_folder_name=DIRECTORY+name;   }
   string            GetFolderName(void)                       const { return this.m_folder_name;           }
//--- Return the object name
   string            GetName(void)                             const { return this.m_name;                  }
//--- Update the object data (implementation in the descendants)
   virtual void      Refresh(void);


No construtor da classe, na sua lista de inicialização, às variáveis-membro da classe são atribuídos valores iniciais:

//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CBaseObj::CBaseObj() : m_global_error(ERR_SUCCESS),      
                       m_hash_sum(0),m_hash_sum_prev(0), 
                       m_is_event(false),m_event_code(0),
                       m_chart_id(::ChartID()),          
                       m_folder_name(DIRECTORY),         
                       m_name("")                        
  {
   ::ZeroMemory(this.m_tick);
   this.m_digits_currency=(#ifdef __MQL5__ (int)::AccountInfoInteger(ACCOUNT_CURRENCY_DIGITS) #else 2 #endif);
   this.m_list_events.Clear();
   this.m_list_events.Sort();
  }
//+------------------------------------------------------------------+

Em seguida, é redefinida a estrutura do tick, é atribuído o valor do número de casas decimais para a moeda da conta, é limpa a lista de evento e à lista de eventos do objeto é atribuído o sinalizador da lista classificada.

Método para adicionar eventos à lista:

//+------------------------------------------------------------------+
//| Add the event object to the list                                 |
//+------------------------------------------------------------------+
bool CBaseObj::EventAdd(const ushort event_id,const long lparam,const double dparam,const string sparam)
  {
   CEventBaseObj *event=new CEventBaseObj(event_id,lparam,dparam,sparam);
   if(event==NULL)
      return false;
   this.m_list_events.Sort();
   if(this.m_list_events.Search(event)>WRONG_VALUE)
     {
      delete event;
      return false;
     }
   return this.m_list_events.Add(event);
  }
//+------------------------------------------------------------------+

Para o método são transferidos o identificador de evento e o valor long, double e string da propriedade do evento. Em seguida, é criado o novo evento com estes parâmetros. Se o mesmo evento já estiver na lista, o objeto de evento será excluído e o método retornará false, caso contrário, o método retornará o resultado da adição do objeto-evento à lista.

Método que retorna o objeto-evento de acordo com o seu índice na lista:

//+------------------------------------------------------------------+
//| Return the object event by its index in the list                 |
//+------------------------------------------------------------------+
CEventBaseObj *CBaseObj::GetEvent(const int shift=WRONG_VALUE,const bool check_out=true)
  {
   int total=this.m_list_events.Total();
   if(total==0 || (!check_out && shift>total-1))
      return NULL;   
   int index=(shift<=0 ? total-1 : shift>total-1 ? 0 : total-shift-1);
   CEventBaseObj *event=this.m_list_events.At(index);
   return(event!=NULL ? event : NULL);
  }
//+------------------------------------------------------------------+

Já consideramos o método anteriormente. Aqui, apenas é adicionado o sinalizador para verificar e ajustar o índice quando seu valor fica fora da lista. Por padrão, o índice -1 é passado para o método e a é verificado se o índice sai da lista. Neste caso, o método retorna o objeto-evento mais recente da lista. Para obter um objeto por seu índice, é necessário passar para o método o índice necessário e o sinalizador para controlar a saída da lista = false. Neste caso, o objeto será retornado (se o índice estiver dentro da lista) ou NULL , se o índice estiver fora da lista.

Também consideramos anteriormente o método que retorna o número de casas decimais num valor double:

//+------------------------------------------------------------------+
//| Return the number of decimal places in the 'double' value        |
//+------------------------------------------------------------------+
int CBaseObj::GetDigits(const double value) const
  {
   string val_str=(string)value;
   int len=::StringLen(val_str);
   int n=len-::StringFind(val_str,".",0)-1;
   if(::StringSubstr(val_str,len-1,1)=="0")
      n--;
   return n;
  }
//+------------------------------------------------------------------+

O novo objeto base está pronto.

Agora, apenas precisamos substituir a classe base CObject em cada um dos objetos base da biblioteca por CBaseObj. Teremos estes objetos:

objeto da classe CAccount:

//+------------------------------------------------------------------+
//| Account class                                                    |
//+------------------------------------------------------------------+
class CAccount : public CBaseObj
  {

objeto da classe CSymbol:

//+------------------------------------------------------------------+
//| Abstract symbol class                                            |
//+------------------------------------------------------------------+
class CSymbol : public CBaseObj
  {

As classes de coleções também são dotadas das propriedades gerais dos objetos:

coleção de eventos de negociação:

//+------------------------------------------------------------------+
//| Collection of account trading events                             |
//+------------------------------------------------------------------+
class CEventsCollection : public CBaseObj
  {

coleção de contas:

//+------------------------------------------------------------------+
//| Account collection                                               |
//+------------------------------------------------------------------+
class CAccountsCollection : public CBaseObj
  {

coleção de símbolos:

//+------------------------------------------------------------------+
//| Symbol collection                                                |
//+------------------------------------------------------------------+
class CSymbolsCollection : public CBaseObj
  {

Agora, todos os objetos criados com base no CBaseObj têm o mesmo conjunto de propriedades e, ao criar novos objetos, não precisamos registrar novamente essas propriedades em cada objeto. Além disso, agora podemos adicionar propriedades iguais para todos os objetos criados com base em tal objeto base. E o mais interessante é que cada um desses objetos agora tem um instrumento para trabalhar com eventos. O evento de cada um dos objetos tem o mesmo conjunto de parâmetros que a função para enviar o evento ao gráfico do programa EventChartCustom(). Assim, simplificamos bastante o desenvolvimento de novos objetos e o aprimoramento de objetos já prontos.


Agora podemos começar a criar eventos de coleção de símbolos.

Eventos de coleção de símbolos

Como sempre, começamos a definir constantes e enumerações. Abrimos o arquivo Defines.mqh e escrevemos nele os dados necessário para rastrear eventos de símbolos.

Como, ao trabalhar com símbolos, eles devem estar presentes na janela "Observação do Mercado" e como seu número é limitado, então
adicionamos aos parâmetros de símbolos uma strings contendo uma substituição de macros indicando o número máximo possível de símbolos localizado simultaneamente na janela "Observação do Mercado":

//--- Symbol parameters
#define CLR_DEFAULT                    (0xFF000000)               // Default color
#define SYMBOLS_COMMON_TOTAL           (1000)                     // Total number of working symbols

A partir da seção de dados para trabalhar com símbolos, transferimos a enumeração de modos para trabalhar com símbolos

//+------------------------------------------------------------------+
//| Data for working with symbols                                    |
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+
//| Modes of working with symbols                                    |
//+------------------------------------------------------------------+
enum ENUM_SYMBOLS_MODE
  {
   SYMBOLS_MODE_CURRENT,                                    // Work with the current symbol only
   SYMBOLS_MODE_DEFINES,                                    // Work with the specified symbol list
   SYMBOLS_MODE_MARKET_WATCH,                               // Work with the Market Watch window symbols
   SYMBOLS_MODE_ALL                                         // Work with the full symbol list
  };
//+------------------------------------------------------------------+

para o arquivo Datas.mqh:

//+------------------------------------------------------------------+
//|                                                        Datas.mqh |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://mql5.com/en/users/artmedia70"
//+------------------------------------------------------------------+
//| Enumerations                                                     |
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+
//| Modes of working with symbols                                    |
//+------------------------------------------------------------------+
enum ENUM_SYMBOLS_MODE
  {
   SYMBOLS_MODE_CURRENT,                                    // Work with the current symbol only
   SYMBOLS_MODE_DEFINES,                                    // Work with the specified symbol list
   SYMBOLS_MODE_MARKET_WATCH,                               // Work with the Market Watch window symbols
   SYMBOLS_MODE_ALL                                         // Work with the full symbol list
  };
//+------------------------------------------------------------------+
//| Data sets                                                        |
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+
//| Major Forex symbols                                              |
//+------------------------------------------------------------------+
string DataSymbolsFXMajors[]=
  {

O motivo desta decisão foi que estes dados são necessários não apenas para a biblioteca, mas também para programas baseados na biblioteca. Além disso, esta enumeração tem a ver mais com os dados gerais do programa do que com os dados da biblioteca. Por exemplo, eles precisarão ser usados junto com muitas outras enumerações como parâmetros de entrada dos programas e, portanto, traduzidos para a linguagem de compilação necessária (o que será feito posteriormente). Sendo assim, vamos deixá-los no Datas.mqh.

Para o local da enumeração transferida do Defines.mqh escrevemos a enumeração contendo a lista de sinalizadores de eventos do símbolo e a enumeração contendo a lista de possíveis eventos do símbolo:

//+------------------------------------------------------------------+
//| Data for working with symbols                                    |
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+
//| List of symbol event flags                                       |
//+------------------------------------------------------------------+
enum ENUM_SYMBOL_EVENT_FLAGS
  {
   SYMBOL_EVENT_FLAG_NO_EVENT                =  0,          // No event
   SYMBOL_EVENT_FLAG_TRADE_MODE              =  1,          // Change order execution permissions
   SYMBOL_EVENT_FLAG_SESSION_DEALS           =  2,          // Change the number of deals in the current session
   SYMBOL_EVENT_FLAG_SESSION_BUY_ORDERS      =  4,          // Change the total number of the current buy orders
   SYMBOL_EVENT_FLAG_SESSION_SELL_ORDERS     =  8,          // Change the total number of the current sell orders
   SYMBOL_EVENT_FLAG_VOLUME                  =  16,         // Change in the last deal volume exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_VOLUME_HIGH_DAY         =  32,         // Change of the maximum volume per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_VOLUME_LOW_DAY          =  64,         // Change of the minimum volume per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SPREAD                  =  128,        // Change of a spread exceeds the specified change value in +/-
   SYMBOL_EVENT_FLAG_STOPLEVEL               =  256,        // Change of a Stop order level exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_FREEZELEVEL             =  512,        // Change of the freeze level exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_BID_LAST                =  1024,       // Change of the Bid or Last price exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_BID_LAST_HIGH           =  2048,       // Change of the maximum Bid or Last price per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_BID_LAST_LOW            =  4096,       // Change of the minimum Bid or Last price per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_ASK                     =  8192,       // Change of the Ask price exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_ASK_HIGH                =  16384,      // Change of the maximum Ask price per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_ASK_LOW                 =  32768,      // Change of the minimum Ask price per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_VOLUME_REAL_DAY         =  65536,      // Change of the real volume per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_VOLUME_HIGH_REAL_DAY    =  131072,     // Change of the maximum real volume per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_VOLUME_LOW_REAL_DAY     =  262144,     // Change of the minimum real volume per day exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_OPTION_STRIKE           =  524288,     // Change of the strike price exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_VOLUME_LIMIT            =  1048576,    // Change of the maximum available total position volume and pending orders in one direction
   SYMBOL_EVENT_FLAG_SWAP_LONG               =  2097152,    // Change swap long
   SYMBOL_EVENT_FLAG_SWAP_SHORT              =  4194304,    // Change swap short
   SYMBOL_EVENT_FLAG_SESSION_VOLUME          =  8388608,    // Change of the total volume of deals in the current session exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_TURNOVER        =  16777216,   // Change of the total turnover in the current session exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_INTEREST        =  33554432,   // Change of the total volume of open positions in the current session exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_BUY_ORD_VOLUME  =  67108864,   // Change of the total volume of buy orders exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_SELL_ORD_VOLUME =  134217728// Change of the total volume of sell orders exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_OPEN            =  268435456// Change of the session open price exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_CLOSE           =  536870912// Change of the session close price exceeds the specified value in +/-
   SYMBOL_EVENT_FLAG_SESSION_AW              =  1073741824  // Change of the average weighted session price exceeds the specified value in +/-
  };
//+------------------------------------------------------------------+
//| List of possible symbol events                                   |
//+------------------------------------------------------------------+
enum ENUM_SYMBOL_EVENT
  {
   SYMBOL_EVENT_NO_EVENT = ACCOUNT_EVENTS_NEXT_CODE,        // No event
   SYMBOL_EVENT_MW_ADD,                                     // Adding a symbol to the Market Watch window
   SYMBOL_EVENT_MW_DEL,                                     // Removing a symbol from the Market Watch window
   SYMBOL_EVENT_MW_SORT,                                    // Sorting symbols in the Market Watch window
   SYMBOL_EVENT_TRADE_DISABLE,                              // Disable order execution
   SYMBOL_EVENT_TRADE_LONGONLY,                             // Allow buy only
   SYMBOL_EVENT_TRADE_SHORTONLY,                            // Allow sell only
   SYMBOL_EVENT_TRADE_CLOSEONLY,                            // Enable close only
   SYMBOL_EVENT_TRADE_FULL,                                 // No trading limitations
   SYMBOL_EVENT_SESSION_DEALS_INC,                          // The increase in the number of deals in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_DEALS_DEC,                          // The decrease in the number of deals in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_BUY_ORDERS_INC,                     // The increase in the total number of buy orders currently exceeds the specified value
   SYMBOL_EVENT_SESSION_BUY_ORDERS_DEC,                     // The decrease in the total number of buy orders currently exceeds the specified value
   SYMBOL_EVENT_SESSION_SELL_ORDERS_INC,                    // The increase in the total number of sell orders currently exceeds the specified value
   SYMBOL_EVENT_SESSION_SELL_ORDERS_DEC,                    // The decrease in the total number of sell orders currently exceeds the specified value
   SYMBOL_EVENT_VOLUME_INC,                                 // Volume increase in the last deal exceeds the specified value
   SYMBOL_EVENT_VOLUME_DEC,                                 // Volume decrease in the last deal exceeds the specified value
   SYMBOL_EVENT_VOLUME_HIGH_DAY_INC,                        // The increase in the maximum volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_HIGH_DAY_DEC,                        // The decrease in the maximum volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_LOW_DAY_INC,                         // The increase in the minimum volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_LOW_DAY_DEC,                         // The decrease in the minimum volume per day exceeds the specified value
   SYMBOL_EVENT_SPREAD_INC,                                 // The increase in a spread exceeds the specified change
   SYMBOL_EVENT_SPREAD_DEC,                                 // The decrease in a spread exceeds the specified change
   SYMBOL_EVENT_STOPLEVEL_INC,                              // The increase of a Stop order level exceeds the specified value
   SYMBOL_EVENT_STOPLEVEL_DEC,                              // The decrease of a Stop order level exceeds the specified value
   SYMBOL_EVENT_FREEZELEVEL_INC,                            // The increase in the freeze level exceeds the specified value
   SYMBOL_EVENT_FREEZELEVEL_DEC,                            // The decrease in the freeze level exceeds the specified value
   SYMBOL_EVENT_BID_LAST_INC,                               // The increase in the Bid or Last price exceeds the specified value
   SYMBOL_EVENT_BID_LAST_DEC,                               // The decrease in the Bid or Last price exceeds the specified value
   SYMBOL_EVENT_BID_LAST_HIGH_INC,                          // The increase in the maximum Bid or Last price per day exceeds the specified value
   SYMBOL_EVENT_BID_LAST_HIGH_DEC,                          // The decrease in the maximum Bid or Last price per day exceeds the specified value relative to the specified price
   SYMBOL_EVENT_BID_LAST_LOW_INC,                           // The increase in the minimum Bid or Last price per day exceeds the specified value relative to the specified price
   SYMBOL_EVENT_BID_LAST_LOW_DEC,                           // The decrease in the minimum Bid or Last price per day exceeds the specified value
   SYMBOL_EVENT_ASK_INC,                                    // The increase in the Ask price exceeds the specified value
   SYMBOL_EVENT_ASK_DEC,                                    // The decrease in the Ask price exceeds the specified value
   SYMBOL_EVENT_ASK_HIGH_INC,                               // The increase in the maximum Ask price per day exceeds the specified value
   SYMBOL_EVENT_ASK_HIGH_DEC,                               // The decrease in the maximum Ask price per day exceeds the specified value
   SYMBOL_EVENT_ASK_LOW_INC,                                // The increase in the minimum Ask price per day exceeds the specified value
   SYMBOL_EVENT_ASK_LOW_DEC,                                // The decrease in the minimum Ask price per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_REAL_DAY_INC,                        // The increase in the real volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_REAL_DAY_DEC,                        // The decrease in the real volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_HIGH_REAL_DAY_INC,                   // The increase in the maximum real volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_HIGH_REAL_DAY_DEC,                   // The decrease in the maximum real volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_LOW_REAL_DAY_INC,                    // The increase in the minimum real volume per day exceeds the specified value
   SYMBOL_EVENT_VOLUME_LOW_REAL_DAY_DEC,                    // The decrease in the minimum real volume per day exceeds the specified value
   SYMBOL_EVENT_OPTION_STRIKE_INC,                          // The increase in the strike price exceeds the specified value
   SYMBOL_EVENT_OPTION_STRIKE_DEC,                          // The decrease in the strike price exceeds the specified value
   SYMBOL_EVENT_VOLUME_LIMIT_INC,                           // The increase in the maximum available total position volume and pending orders in one direction
   SYMBOL_EVENT_VOLUME_LIMIT_DEC,                           // The decrease in the maximum available total position volume and pending orders in one direction
   SYMBOL_EVENT_SWAP_LONG_INC,                              // The increase in the swap long
   SYMBOL_EVENT_SWAP_LONG_DEC,                              // The decrease in the swap long
   SYMBOL_EVENT_SWAP_SHORT_INC,                             // The increase in the swap short
   SYMBOL_EVENT_SWAP_SHORT_DEC,                             // The decrease in the swap short
   SYMBOL_EVENT_SESSION_VOLUME_INC,                         // The increase in the total volume of deals in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_VOLUME_DEC,                         // The decrease in the total volume of deals in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_TURNOVER_INC,                       // The increase in the total turnover in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_TURNOVER_DEC,                       // The decrease in the total turnover in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_INTEREST_INC,                       // The increase in the total volume of open positions in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_INTEREST_DEC,                       // The decrease in the total volume of open positions in the current session exceeds the specified value
   SYMBOL_EVENT_SESSION_BUY_ORD_VOLUME_INC,                 // The increase in the total volume of buy orders exceeds the specified value
   SYMBOL_EVENT_SESSION_BUY_ORD_VOLUME_DEC,                 // The decrease in the total volume of buy orders exceeds the specified value
   SYMBOL_EVENT_SESSION_SELL_ORD_VOLUME_INC,                // The increase in the total volume of sell orders exceeds the specified value
   SYMBOL_EVENT_SESSION_SELL_ORD_VOLUME_DEC,                // The decrease in the total volume of sell orders exceeds the specified value
   SYMBOL_EVENT_SESSION_OPEN_INC,                           // The increase in the session open price exceeds the specified value relative to the specified price
   SYMBOL_EVENT_SESSION_OPEN_DEC,                           // The decrease in the session open price exceeds the specified value relative to the specified price
   SYMBOL_EVENT_SESSION_CLOSE_INC,                          // The increase in the session close price exceeds the specified value relative to the specified price
   SYMBOL_EVENT_SESSION_CLOSE_DEC,                          // The decrease in the session close price exceeds the specified value relative to the specified price
   SYMBOL_EVENT_SESSION_AW_INC,                             // The increase in the average weighted session price exceeds the specified value
   SYMBOL_EVENT_SESSION_AW_DEC,                             // The decrease in the average weighted session price exceeds the specified value
  };
#define SYMBOL_EVENTS_NEXT_CODE       (SYMBOL_EVENT_SESSION_AW_DEC+1)   // The code of the next event after the last symbol event code
//+------------------------------------------------------------------+

Aqui, tudo acontece exatamente como com as enumerações de sinalizadores, de possíveis eventos de conta e de eventos de negociação. Na quarta parte da descrição da biblioteca nós consideramos os sinalizadores de eventos e os identificadores de eventos.

Para classificar os símbolos de acordo com a sua localização na janela "Observação do Mercado", adicionamos mais uma propriedade de símbolo inteira:

//+------------------------------------------------------------------+
//| Symbol integer properties                                        |
//+------------------------------------------------------------------+
enum ENUM_SYMBOL_PROP_INTEGER
  {
   SYMBOL_PROP_STATUS = 0,                                  // Symbol status
   SYMBOL_PROP_INDEX_MW,                                    // Symbol index in the Market Watch window
   SYMBOL_PROP_CUSTOM,                                      // Custom symbol flag
   SYMBOL_PROP_CHART_MODE,                                  // The price type used for generating bars – Bid or Last (from the ENUM_SYMBOL_CHART_MODE enumeration)
   SYMBOL_PROP_EXIST,                                       // Flag indicating that the symbol under this name exists
   SYMBOL_PROP_SELECT,                                      // The indication that the symbol is selected in Market Watch
   SYMBOL_PROP_VISIBLE,                                     // The indication that the symbol is displayed in Market Watch
   SYMBOL_PROP_SESSION_DEALS,                               // The number of deals in the current session 
   SYMBOL_PROP_SESSION_BUY_ORDERS,                          // The total number of Buy orders at the moment
   SYMBOL_PROP_SESSION_SELL_ORDERS,                         // The total number of Sell orders at the moment
   SYMBOL_PROP_VOLUME,                                      // Last deal volume
   SYMBOL_PROP_VOLUMEHIGH,                                  // Maximum volume within a day
   SYMBOL_PROP_VOLUMELOW,                                   // Minimum volume within a day
   SYMBOL_PROP_TIME,                                        // Latest quote time
   SYMBOL_PROP_DIGITS,                                      // Number of decimal places
   SYMBOL_PROP_DIGITS_LOTS,                                 // Number of decimal places for a lot
   SYMBOL_PROP_SPREAD,                                      // Spread in points
   SYMBOL_PROP_SPREAD_FLOAT,                                // Floating spread flag
   SYMBOL_PROP_TICKS_BOOKDEPTH,                             // Maximum number of orders displayed in the Depth of Market
   SYMBOL_PROP_TRADE_CALC_MODE,                             // Contract price calculation method (from the ENUM_SYMBOL_CALC_MODE enumeration)
   SYMBOL_PROP_TRADE_MODE,                                  // Order execution type (from the ENUM_SYMBOL_TRADE_MODE enumeration)
   SYMBOL_PROP_START_TIME,                                  // Symbol trading start date (usually used for futures)
   SYMBOL_PROP_EXPIRATION_TIME,                             // Symbol trading end date (usually used for futures)
   SYMBOL_PROP_TRADE_STOPS_LEVEL,                           // Minimum distance in points from the current close price for setting Stop orders
   SYMBOL_PROP_TRADE_FREEZE_LEVEL,                          // Freeze distance for trading operations (in points)
   SYMBOL_PROP_TRADE_EXEMODE,                               // Deal execution mode (from the ENUM_SYMBOL_TRADE_EXECUTION enumeration)
   SYMBOL_PROP_SWAP_MODE,                                   // Swap calculation model (from the ENUM_SYMBOL_SWAP_MODE enumeration)
   SYMBOL_PROP_SWAP_ROLLOVER3DAYS,                          // Triple-day swap (from the ENUM_DAY_OF_WEEK enumeration)
   SYMBOL_PROP_MARGIN_HEDGED_USE_LEG,                       // Calculating hedging margin using the larger leg (Buy or Sell)
   SYMBOL_PROP_EXPIRATION_MODE,                             // Flags of allowed order expiration modes
   SYMBOL_PROP_FILLING_MODE,                                // Flags of allowed order filling modes
   SYMBOL_PROP_ORDER_MODE,                                  // Flags of allowed order types
   SYMBOL_PROP_ORDER_GTC_MODE,                              // Expiration of Stop Loss and Take Profit orders if SYMBOL_EXPIRATION_MODE=SYMBOL_EXPIRATION_GTC (from the ENUM_SYMBOL_ORDER_GTC_MODE enumeration)
   SYMBOL_PROP_OPTION_MODE,                                 // Option type (from the ENUM_SYMBOL_OPTION_MODE enumeration)
   SYMBOL_PROP_OPTION_RIGHT,                                // Option right (Call/Put) (from the ENUM_SYMBOL_OPTION_RIGHT enumeration)
   //--- skipped property
   SYMBOL_PROP_BACKGROUND_COLOR                             // The color of the background used for the symbol in Market Watch
  }; 
#define SYMBOL_PROP_INTEGER_TOTAL    (36)                   // Total number of integer properties
#define SYMBOL_PROP_INTEGER_SKIP     (1)                    // Number of symbol integer properties not used in sorting
//+------------------------------------------------------------------+

Como acrescentamos uma nova propriedade, temos de aumentar o número total de propriedades inteiras para 36, em vez das anteriores 35.

Finalmente, à lista de critérios possíveis para classificar símbolos adicionamos esta nova propriedade:




//+------------------------------------------------------------------+
//| Possible symbol sorting criteria                                 |
//+------------------------------------------------------------------+
#define FIRST_SYM_DBL_PROP          (SYMBOL_PROP_INTEGER_TOTAL-SYMBOL_PROP_INTEGER_SKIP)
#define FIRST_SYM_STR_PROP          (SYMBOL_PROP_INTEGER_TOTAL-SYMBOL_PROP_INTEGER_SKIP+SYMBOL_PROP_DOUBLE_TOTAL-SYMBOL_PROP_DOUBLE_SKIP)
enum ENUM_SORT_SYMBOLS_MODE
  {
//--- Sort by integer properties
   SORT_BY_SYMBOL_STATUS = 0,                               // Sort by symbol status
   SORT_BY_SYMBOL_INDEX_MW,                                 // Sort by index in the Market Watch window
   SORT_BY_SYMBOL_CUSTOM,                                   // Sort by custom symbol property
   SORT_BY_SYMBOL_CHART_MODE,                               // Sort by price type for constructing bars – Bid or Last (from the ENUM_SYMBOL_CHART_MODE enumeration)
   SORT_BY_SYMBOL_EXIST,                                    // Sort by the flag that a symbol with such a name exists
   SORT_BY_SYMBOL_SELECT,                                   // Sort by the flag indicating that a symbol is selected in Market Watch
   SORT_BY_SYMBOL_VISIBLE,                                  // Sort by the flag indicating that a selected symbol is displayed in Market Watch
   SORT_BY_SYMBOL_SESSION_DEALS,                            // Sort by the number of deals in the current session 
   SORT_BY_SYMBOL_SESSION_BUY_ORDERS,                       // Sort by the total number of current buy orders
   SORT_BY_SYMBOL_SESSION_SELL_ORDERS,                      // Sort by the total number of current sell orders
   SORT_BY_SYMBOL_VOLUME,                                   // Sort by last deal volume
   SORT_BY_SYMBOL_VOLUMEHIGH,                               // Sort by maximum volume for a day
   SORT_BY_SYMBOL_VOLUMELOW,                                // Sort by minimum volume for a day
   SORT_BY_SYMBOL_TIME,                                     // Sort by the last quote time
   SORT_BY_SYMBOL_DIGITS,                                   // Sort by a number of decimal places
   SORT_BY_SYMBOL_DIGITS_LOT,                               // Sort by a number of decimal places in a lot
   SORT_BY_SYMBOL_SPREAD,                                   // Sort by spread in points
   SORT_BY_SYMBOL_SPREAD_FLOAT,                             // Sort by floating spread
   SORT_BY_SYMBOL_TICKS_BOOKDEPTH,                          // Sort by a maximum number of requests displayed in the market depth
   SORT_BY_SYMBOL_TRADE_CALC_MODE,                          // Sort by contract price calculation method (from the ENUM_SYMBOL_CALC_MODE enumeration)
   SORT_BY_SYMBOL_TRADE_MODE,                               // Sort by order execution type (from the ENUM_SYMBOL_TRADE_MODE enumeration)
   SORT_BY_SYMBOL_START_TIME,                               // Sort by an instrument trading start date (usually used for futures)
   SORT_BY_SYMBOL_EXPIRATION_TIME,                          // Sort by an instrument trading end date (usually used for futures)
   SORT_BY_SYMBOL_TRADE_STOPS_LEVEL,                        // Sort by the minimum indent from the current close price (in points) for setting Stop orders
   SORT_BY_SYMBOL_TRADE_FREEZE_LEVEL,                       // Sort by trade operation freeze distance (in points)
   SORT_BY_SYMBOL_TRADE_EXEMODE,                            // Sort by trade execution mode (from the ENUM_SYMBOL_TRADE_EXECUTION enumeration)
   SORT_BY_SYMBOL_SWAP_MODE,                                // Sort by swap calculation model (from the ENUM_SYMBOL_SWAP_MODE enumeration)
   SORT_BY_SYMBOL_SWAP_ROLLOVER3DAYS,                       // Sort by week day for accruing a triple swap (from the ENUM_DAY_OF_WEEK enumeration)
   SORT_BY_SYMBOL_MARGIN_HEDGED_USE_LEG,                    // Sort by the calculation mode of a hedged margin using the larger leg (Buy or Sell)
   SORT_BY_SYMBOL_EXPIRATION_MODE,                          // Sort by flags of allowed order expiration modes
   SORT_BY_SYMBOL_FILLING_MODE,                             // Sort by flags of allowed order filling modes
   SORT_BY_SYMBOL_ORDER_MODE,                               // Sort by flags of allowed order types
   SORT_BY_SYMBOL_ORDER_GTC_MODE,                           // Sort by StopLoss and TakeProfit orders lifetime
   SORT_BY_SYMBOL_OPTION_MODE,                              // Sort by option type (from the ENUM_SYMBOL_OPTION_MODE enumeration)
   SORT_BY_SYMBOL_OPTION_RIGHT,                             // Sort by option right (Call/Put) (from the ENUM_SYMBOL_OPTION_RIGHT enumeration)
//--- Sort by real properties
   SORT_BY_SYMBOL_BID = FIRST_SYM_DBL_PROP,                 // Sort by Bid
   SORT_BY_SYMBOL_BIDHIGH,                                  // Sort by maximum Bid for a day
   SORT_BY_SYMBOL_BIDLOW,                                   // Sort by minimum Bid for a day
   SORT_BY_SYMBOL_ASK,                                      // Sort by Ask
   SORT_BY_SYMBOL_ASKHIGH,                                  // Sort by maximum Ask for a day
   SORT_BY_SYMBOL_ASKLOW,                                   // Sort by minimum Ask for a day
   SORT_BY_SYMBOL_LAST,                                     // Sort by the last deal price
   SORT_BY_SYMBOL_LASTHIGH,                                 // Sort by maximum Last for a day
   SORT_BY_SYMBOL_LASTLOW,                                  // Sort by minimum Last for a day
   SORT_BY_SYMBOL_VOLUME_REAL,                              // Sort by Volume for a day
   SORT_BY_SYMBOL_VOLUMEHIGH_REAL,                          // Sort by maximum Volume for a day
   SORT_BY_SYMBOL_VOLUMELOW_REAL,                           // Sort by minimum Volume for a day
   SORT_BY_SYMBOL_OPTION_STRIKE,                            // Sort by an option execution price
   SORT_BY_SYMBOL_POINT,                                    // Sort by a single point value
   SORT_BY_SYMBOL_TRADE_TICK_VALUE,                         // Sort by SYMBOL_TRADE_TICK_VALUE_PROFIT value
   SORT_BY_SYMBOL_TRADE_TICK_VALUE_PROFIT,                  // Sort by a calculated tick price for a profitable position
   SORT_BY_SYMBOL_TRADE_TICK_VALUE_LOSS,                    // Sort by a calculated tick price for a loss-making position
   SORT_BY_SYMBOL_TRADE_TICK_SIZE,                          // Sort by a minimum price change
   SORT_BY_SYMBOL_TRADE_CONTRACT_SIZE,                      // Sort by a trading contract size
   SORT_BY_SYMBOL_TRADE_ACCRUED_INTEREST,                   // Sort by accrued interest
   SORT_BY_SYMBOL_TRADE_FACE_VALUE,                         // Sort by face value
   SORT_BY_SYMBOL_TRADE_LIQUIDITY_RATE,                     // Sort by liquidity rate
   SORT_BY_SYMBOL_VOLUME_MIN,                               // Sort by a minimum volume for performing a deal
   SORT_BY_SYMBOL_VOLUME_MAX,                               // Sort by a maximum volume for performing a deal
   SORT_BY_SYMBOL_VOLUME_STEP,                              // Sort by a minimum volume change step for deal execution
   SORT_BY_SYMBOL_VOLUME_LIMIT,                             // Sort by a maximum allowed aggregate volume of an open position and pending orders in one direction
   SORT_BY_SYMBOL_SWAP_LONG,                                // Sort by a long swap value
   SORT_BY_SYMBOL_SWAP_SHORT,                               // Sort by a short swap value
   SORT_BY_SYMBOL_MARGIN_INITIAL,                           // Sort by an initial margin
   SORT_BY_SYMBOL_MARGIN_MAINTENANCE,                       // Sort by a maintenance margin for an instrument
   SORT_BY_SYMBOL_MARGIN_LONG_INITIAL,                      // Sort by initial margin requirement applicable to Long orders
   SORT_BY_SYMBOL_MARGIN_BUY_STOP_INITIAL,                  // Sort by initial margin requirement applicable to BuyStop orders
   SORT_BY_SYMBOL_MARGIN_BUY_LIMIT_INITIAL,                 // Sort by initial margin requirement applicable to BuyLimit orders
   SORT_BY_SYMBOL_MARGIN_BUY_STOPLIMIT_INITIAL,             // Sort by initial margin requirement applicable to BuyStopLimit orders
   SORT_BY_SYMBOL_MARGIN_LONG_MAINTENANCE,                  // Sort by maintenance margin requirement applicable to Long orders
   SORT_BY_SYMBOL_MARGIN_BUY_STOP_MAINTENANCE,              // Sort by maintenance margin requirement applicable to BuyStop orders
   SORT_BY_SYMBOL_MARGIN_BUY_LIMIT_MAINTENANCE,             // Sort by maintenance margin requirement applicable to BuyLimit orders
   SORT_BY_SYMBOL_MARGIN_BUY_STOPLIMIT_MAINTENANCE,         // Sort by maintenance margin requirement applicable to BuyStopLimit orders
   SORT_BY_SYMBOL_MARGIN_SHORT_INITIAL,                     // Sort by initial margin requirement applicable to Short orders
   SORT_BY_SYMBOL_MARGIN_SELL_STOP_INITIAL,                 // Sort by initial margin requirement applicable to SellStop orders
   SORT_BY_SYMBOL_MARGIN_SELL_LIMIT_INITIAL,                // Sort by initial margin requirement applicable to SellLimit orders
   SORT_BY_SYMBOL_MARGIN_SELL_STOPLIMIT_INITIAL,            // Sort by initial margin requirement applicable to SellStopLimit orders
   SORT_BY_SYMBOL_MARGIN_SHORT_MAINTENANCE,                 // Sort by maintenance margin requirement applicable to Short orders
   SORT_BY_SYMBOL_MARGIN_SELL_STOP_MAINTENANCE,             // Sort by maintenance margin requirement applicable to SellStop orders
   SORT_BY_SYMBOL_MARGIN_SELL_LIMIT_MAINTENANCE,            // Sort by maintenance margin requirement applicable to SellLimit orders
   SORT_BY_SYMBOL_MARGIN_SELL_STOPLIMIT_MAINTENANCE,        // Sort by maintenance margin requirement applicable to SellStopLimit orders
   SORT_BY_SYMBOL_SESSION_VOLUME,                           // Sort by summary volume of the current session deals
   SORT_BY_SYMBOL_SESSION_TURNOVER,                         // Sort by the summary turnover of the current session
   SORT_BY_SYMBOL_SESSION_INTEREST,                         // Sort by the summary open interest
   SORT_BY_SYMBOL_SESSION_BUY_ORDERS_VOLUME,                // Sort by the current volume of Buy orders
   SORT_BY_SYMBOL_SESSION_SELL_ORDERS_VOLUME,               // Sort by the current volume of Sell orders
   SORT_BY_SYMBOL_SESSION_OPEN,                             // Sort by a session Open price
   SORT_BY_SYMBOL_SESSION_CLOSE,                            // Sort by a session Close price
   SORT_BY_SYMBOL_SESSION_AW,                               // Sort by an average weighted price of the current session
   SORT_BY_SYMBOL_SESSION_PRICE_SETTLEMENT,                 // Sort by a settlement price of the current session
   SORT_BY_SYMBOL_SESSION_PRICE_LIMIT_MIN,                  // Sort by a minimum price of the current session 
   SORT_BY_SYMBOL_SESSION_PRICE_LIMIT_MAX,                  // Sort by a maximum price of the current session
   SORT_BY_SYMBOL_MARGIN_HEDGED,                            // Sort by a contract size or a margin value per one lot of hedged positions
//--- Sort by string properties
   SORT_BY_SYMBOL_NAME = FIRST_SYM_STR_PROP,                // Sort by a symbol name
   SORT_BY_SYMBOL_BASIS,                                    // Sort by an underlying asset of a derivative
   SORT_BY_SYMBOL_CURRENCY_BASE,                            // Sort by a base currency of a symbol
   SORT_BY_SYMBOL_CURRENCY_PROFIT,                          // Sort by a profit currency
   SORT_BY_SYMBOL_CURRENCY_MARGIN,                          // Sort by a margin currency
   SORT_BY_SYMBOL_BANK,                                     // Sort by a feeder of the current quote
   SORT_BY_SYMBOL_DESCRIPTION,                              // Sort by a symbol string description
   SORT_BY_SYMBOL_FORMULA,                                  // Sort by the formula used for custom symbol pricing
   SORT_BY_SYMBOL_ISIN,                                     // Sort by the name of a symbol in the ISIN system
   SORT_BY_SYMBOL_PAGE,                                     // Sort by an address of the web page containing symbol information
   SORT_BY_SYMBOL_PATH                                      // Sort by a path in the symbol tree
  };
//+------------------------------------------------------------------+

A questão com o arquivo Defines.mqh fica por aqui.

Agora é preciso aprimorar a classe do objeto-símbolo. Como monitoraremos algumas propriedades do símbolo para o alterar, precisamos comparar o valor atual com o valor anterior, quer em termos absolutos, quer para aumentar um valor limite predeterminado. Para fazer isso, precisamos criar uma estrutura de propriedades de símbolo e comparar os campos da estrutura dos valores atuais com os campos da estrutura dos valores anteriores. Discutimos a lógica para determinar os eventos de um objeto ao criar o acompanhamento de eventos da conta. Aqui faremos exatamente o mesmo, exceto que agora já temos no objeto base métodos preparados para armazenar e enviar eventos para o programa.

Inserimos na classe CSymbol o arquivo do objeto base , na seção privada da classe criamos a estrutura de acompanhamento de propriedades do símbolo e declaramos duas variáveis desta estrutura para armazenar o estado atual e anterior das propriedades do símbolo:

//+------------------------------------------------------------------+
//|                                                       Symbol.mqh |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
#property strict    // Necessary for mql4
//+------------------------------------------------------------------+
//| Include files                                                    |
//+------------------------------------------------------------------+
#include "..\BaseObj.mqh"
//+------------------------------------------------------------------+
//| Abstract symbol class                                            |
//+------------------------------------------------------------------+
class CSymbol : public CBaseObj
  {
private:
   struct MqlDataSymbol
     {
      //--- Symbol integer properties
      ENUM_SYMBOL_TRADE_MODE trade_mode;     // SYMBOL_TRADE_MODE Order filling modes
      long session_deals;                    // SYMBOL_SESSION_DEALS The number of deals in the current session 
      long session_buy_orders;               // SYMBOL_SESSION_BUY_ORDERS The total number of current buy orders
      long session_sell_orders;              // SYMBOL_SESSION_SELL_ORDERS The total number of current sell orders
      long volume;                           // SYMBOL_VOLUME Last deal volume
      long volume_high_day;                  // SYMBOL_VOLUMEHIGH Maximum volume within a day
      long volume_low_day;                   // SYMBOL_VOLUMELOW Minimum volume within a day
      int spread;                            // SYMBOL_SPREAD Spread in points
      int stops_level;                       // SYMBOL_TRADE_STOPS_LEVEL Minimum distance in points from the current close price for setting Stop orders
      int freeze_level;                      // SYMBOL_TRADE_FREEZE_LEVEL Freeze distance for trading operations (in points)
      
      //--- Symbol real properties
      double bid_last;                       // SYMBOL_BID/SYMBOL_LAST Bid - the best sell offer/Last deal price
      double bid_last_high;                  // SYMBOL_BIDHIGH/SYMBOL_LASTHIGH Maximum Bid within the day/Maximum Last per day
      double bid_last_low;                   // SYMBOL_BIDLOW/SYMBOL_LASTLOW Minimum Bid within the day/Minimum Last per day
      double ask;                            // SYMBOL_ASK Ask - nest buy offer
      double ask_high;                       // SYMBOL_ASKHIGH Maximum Ask of the day
      double ask_low;                        // SYMBOL_ASKLOW Minimum Ask of the day
      double volume_real_day;                // SYMBOL_VOLUME_REAL Real Volume of the day
      double volume_high_real_day;           // SYMBOL_VOLUMEHIGH_REAL Maximum real Volume of the day
      double volume_low_real_day;            // SYMBOL_VOLUMELOW_REAL Minimum real Volume of the day
      double option_strike;                  // SYMBOL_OPTION_STRIKE Strike price
      double volume_limit;                   // SYMBOL_VOLUME_LIMIT Maximum permissible total volume for a position and pending orders in one direction
      double swap_long;                      // SYMBOL_SWAP_LONG Long swap value
      double swap_short;                     // SYMBOL_SWAP_SHORT Short swap value
      double session_volume;                 // SYMBOL_SESSION_VOLUME The total volume of deals in the current session
      double session_turnover;               // SYMBOL_SESSION_TURNOVER The total turnover in the current session
      double session_interest;               // SYMBOL_SESSION_INTEREST The total volume of open positions
      double session_buy_ord_volume;         // SYMBOL_SESSION_BUY_ORDERS_VOLUME The total volume of Buy orders at the moment
      double session_sell_ord_volume;        // SYMBOL_SESSION_SELL_ORDERS_VOLUME The total volume of Sell orders at the moment
      double session_open;                   // SYMBOL_SESSION_OPEN Session open price
      double session_close;                  // SYMBOL_SESSION_CLOSE Session close price
      double session_aw;                     // SYMBOL_SESSION_AW The average weighted price of the session
     };
   MqlDataSymbol    m_struct_curr_symbol;    // Current symbol data
   MqlDataSymbol    m_struct_prev_symbol;    // Previous symbol data
//---

Em seguida, declaramos as variáveis-membros da classe para armazenar os valores controlados especificados de alteração de propriedades, os valores da mudança e os sinalizadores que indicam se os eventos monitorados existem:

   //--- Execution
   bool              m_is_change_trade_mode;                   // Flag of changing trading mode for a symbol
   //--- Current session deals
   long              m_control_session_deals_inc;              // Controlled value of the growth of the number of deals
   long              m_control_session_deals_dec;              // Controlled value of the decrease in the number of deals
   long              m_changed_session_deals_value;            // Value of change in the number of deals
   bool              m_is_change_session_deals_inc;            // Flag of a change in the number of deals exceeding the growth value
   bool              m_is_change_session_deals_dec;            // Flag of a change in the number of deals exceeding the decrease value
   //--- Buy orders of the current session
   long              m_control_session_buy_ord_inc;            // Controlled value of the growth of the number of Buy orders
   long              m_control_session_buy_ord_dec;            // Controlled value of the decrease in the number of Buy orders
   long              m_changed_session_buy_ord_value;          // Buy orders change value
   bool              m_is_change_session_buy_ord_inc;          // Flag of a change in the number of Buy orders exceeding the growth value
   bool              m_is_change_session_buy_ord_dec;          // Flag of a change in the number of Buy orders being less than the growth value
   //--- Sell orders of the current session
   long              m_control_session_sell_ord_inc;           // Controlled value of the growth of the number of Sell orders
   long              m_control_session_sell_ord_dec;           // Controlled value of the decrease in the number of Sell orders
   long              m_changed_session_sell_ord_value;         // Sell orders change value
   bool              m_is_change_session_sell_ord_inc;         // Flag of a change in the number of Sell orders exceeding the growth value
   bool              m_is_change_session_sell_ord_dec;         // Flag of a change in the number of Sell orders exceeding the decrease value
   //--- Volume of the last deal
   long              m_control_volume_inc;                     // Controlled value of the volume growth in the last deal
   long              m_control_volume_dec;                     // Controlled value of the volume decrease in the last deal
   long              m_changed_volume_value;                   // Value of the volume change in the last deal
   bool              m_is_change_volume_inc;                   // Flag of the volume change in the last deal exceeding the growth value
   bool              m_is_change_volume_dec;                   // Flag of the volume change in the last deal being less than the growth value
   //--- Maximum volume within a day
   long              m_control_volume_high_day_inc;            // Controlled value of the maximum volume growth for a day
   long              m_control_volume_high_day_dec;            // Controlled value of the maximum volume decrease for a day
   long              m_changed_volume_high_day_value;          // Maximum volume change value within a day
   bool              m_is_change_volume_high_day_inc;          // Flag of the maximum day volume exceeding the growth value
   bool              m_is_change_volume_high_day_dec;          // Flag of the maximum day volume exceeding the decrease value
   //--- Minimum volume within a day
   long              m_control_volume_low_day_inc;             // Controlled value of the minimum volume growth for a day
   long              m_control_volume_low_day_dec;             // Controlled value of the minimum volume decrease for a day
   long              m_changed_volume_low_day_value;           // Minimum volume change value within a day
   bool              m_is_change_volume_low_day_inc;           // Flag of the minimum day volume exceeding the growth value
   bool              m_is_change_volume_low_day_dec;           // Flag of the minimum day volume exceeding the decrease value
   //--- Spread
   int               m_control_spread_inc;                     // Controlled spread growth value in points
   int               m_control_spread_dec;                     // Controlled spread decrease value in points
   int               m_changed_spread_value;                   // Spread change value in points
   bool              m_is_change_spread_inc;                   // Flag of spread change in points exceeding the growth value
   bool              m_is_change_spread_dec;                   // Flag of spread change in points exceeding the decrease value
   //--- StopLevel
   int               m_control_stops_level_inc;                // Controlled StopLevel growth value in points
   int               m_control_stops_level_dec;                // Controlled StopLevel decrease value in points
   int               m_changed_stops_level_value;              // StopLevel change value in points
   bool              m_is_change_stops_level_inc;              // Flag of StopLevel change in points exceeding the growth value
   bool              m_is_change_stops_level_dec;              // Flag of StopLevel change in points exceeding the decrease value
   //--- Freeze distance
   int               m_control_freeze_level_inc;               // Controlled FreezeLevel growth value in points
   int               m_control_freeze_level_dec;               // Controlled FreezeLevel decrease value in points
   int               m_changed_freeze_level_value;             // FreezeLevel change value in points
   bool              m_is_change_freeze_level_inc;             // Flag of FreezeLevel change in points exceeding the growth value
   bool              m_is_change_freeze_level_dec;             // Flag of FreezeLevel change in points exceeding the decrease value
   
   //--- Bid/Last
   double            m_control_bid_last_inc;                   // Controlled value of Bid or Last price growth
   double            m_control_bid_last_dec;                   // Controlled value of Bid or Last price decrease
   double            m_changed_bid_last_value;                 // Bid or Last price change value
   bool              m_is_change_bid_last_inc;                 // Flag of Bid or Last price change exceeding the growth value
   bool              m_is_change_bid_last_dec;                 // Flag of Bid or Last price change exceeding the decrease value
   //--- Maximum Bid/Last of the day
   double            m_control_bid_last_high_inc;              // Controlled growth value of the maximum Bid or Last price of the day
   double            m_control_bid_last_high_dec;              // Controlled decrease value of the maximum Bid or Last price of the day
   double            m_changed_bid_last_high_value;            // Maximum Bid or Last change value for the day
   bool              m_is_change_bid_last_high_inc;            // Flag of the maximum Bid or Last price change for the day exceeding the growth value
   bool              m_is_change_bid_last_high_dec;            // Flag of the maximum Bid or Last price change for the day exceeding the decrease value
   //--- Minimum Bid/Last of the day
   double            m_control_bid_last_low_inc;               // Controlled growth value of the minimum Bid or Last price of the day
   double            m_control_bid_last_low_dec;               // Controlled decrease value of the minimum Bid or Last price of the day
   double            m_changed_bid_last_low_value;             // Minimum Bid or Last change value for the day
   bool              m_is_change_bid_last_low_inc;             // Flag of the minimum Bid or Last price change for the day exceeding the growth value
   bool              m_is_change_bid_last_low_dec;             // Flag of the minimum Bid or Last price change for the day exceeding the decrease value
   //--- Ask
   double            m_control_ask_inc;                        // Controlled value of the Ask price growth
   double            m_control_ask_dec;                        // Controlled value of the Ask price decrease
   double            m_changed_ask_value;                      // Ask price change value
   bool              m_is_change_ask_inc;                      // Flag of the Ask price change exceeding the growth value
   bool              m_is_change_ask_dec;                      // Flag of the Ask price change exceeding the decrease value
   //--- Maximum Ask price for the day
   double            m_control_ask_high_inc;                   // Controlled growth value of the maximum Ask price of the day
   double            m_control_ask_high_dec;                   // Controlled decrease value of the maximum Ask price of the day
   double            m_changed_ask_high_value;                 // Maximum Ask price change value for the day
   bool              m_is_change_ask_high_inc;                 // Flag of the maximum Ask price change for the day exceeding the growth value
   bool              m_is_change_ask_high_dec;                 // Flag of the maximum Ask price change for the day exceeding the decrease value
   //--- Minimum Ask price for the day
   double            m_control_ask_low_inc;                    // Controlled growth value of the minimum Ask price of the day
   double            m_control_ask_low_dec;                    // Controlled decrease value of the minimum Ask price of the day
   double            m_changed_ask_low_value;                  // Minimum Ask price change value for the day
   bool              m_is_change_ask_low_inc;                  // Flag of the minimum Ask price change for the day exceeding the growth value
   bool              m_is_change_ask_low_dec;                  // Flag of the minimum Ask price change for the day exceeding the decrease value
   //--- Real Volume for the day
   double            m_control_volume_real_inc;                // Controlled value of the real volume growth of the day
   double            m_control_volume_real_dec;                // Controlled value of the real volume decrease of the day
   double            m_changed_volume_real_value;              // Real volume change value of the day
   bool              m_is_change_volume_real_inc;              // Flag of the real volume change for the day exceeding the growth value
   bool              m_is_change_volume_real_dec;              // Flag of the real volume change for the day exceeding the decrease value
   //--- Maximum real volume for the day
   double            m_control_volume_high_real_day_inc;       // Controlled value of the maximum real volume growth of the day
   double            m_control_volume_high_real_day_dec;       // Controlled value of the maximum real volume decrease of the day
   double            m_changed_volume_high_real_day_value;     // Maximum real volume change value of the day
   bool              m_is_change_volume_high_real_day_inc;     // Flag of the maximum real volume change for the day exceeding the growth value
   bool              m_is_change_volume_high_real_day_dec;     // Flag of the maximum real volume change for the day exceeding the decrease value
   //--- Minimum real volume for the day
   double            m_control_volume_low_real_day_inc;        // Controlled value of the minimum real volume growth of the day
   double            m_control_volume_low_real_day_dec;        // Controlled value of the minimum real volume decrease of the day
   double            m_changed_volume_low_real_day_value;      // Minimum real volume change value of the day
   bool              m_is_change_volume_low_real_day_inc;      // Flag of the minimum real volume change for the day exceeding the growth value
   bool              m_is_change_volume_low_real_day_dec;      // Flag of the minimum real volume change for the day exceeding the decrease value
   //--- Strike price
   double            m_control_option_strike_inc;              // Controlled value of the strike price growth
   double            m_control_option_strike_dec;              // Controlled value of the strike price decrease
   double            m_changed_option_strike_value;            // Strike price change value
   bool              m_is_change_option_strike_inc;            // Flag of the strike price change exceeding the growth value
   bool              m_is_change_option_strike_dec;            // Flag of the strike price change exceeding the decrease value
   //--- Total volume of positions and orders
   double            m_changed_volume_limit_value;             // Minimum total volume change value
   bool              m_is_change_volume_limit_inc;             // Flag of the minimum total volume increase
   bool              m_is_change_volume_limit_dec;             // Flag of the minimum total volume decrease
   //---  Swap long
   double            m_changed_swap_long_value;                // Swap long change value
   bool              m_is_change_swap_long_inc;                // Flag of the swap long increase
   bool              m_is_change_swap_long_dec;                // Flag of the swap long decrease
   //---  Swap short
   double            m_changed_swap_short_value;               // Swap short change value
   bool              m_is_change_swap_short_inc;               // Flag of the swap short increase
   bool              m_is_change_swap_short_dec;               // Flag of the swap short decrease
   //--- The total volume of deals in the current session
   double            m_control_session_volume_inc;             // Controlled value of the total trade volume growth in the current session
   double            m_control_session_volume_dec;             // Controlled value of the total trade volume decrease in the current session
   double            m_changed_session_volume_value;           // The total deal volume change value in the current session
   bool              m_is_change_session_volume_inc;           // Flag of total trade volume change in the current session exceeding the growth value
   bool              m_is_change_session_volume_dec;           // Flag of total trade volume change in the current session exceeding the decrease value
   //--- The total turnover in the current session
   double            m_control_session_turnover_inc;           // Controlled value of the total turnover growth in the current session
   double            m_control_session_turnover_dec;           // Controlled value of the total turnover decrease in the current session
   double            m_changed_session_turnover_value;         // Total turnover change value in the current session
   bool              m_is_change_session_turnover_inc;         // Flag of total turnover change in the current session exceeding the growth value
   bool              m_is_change_session_turnover_dec;         // Flag of total turnover change in the current session exceeding the decrease value
   //--- The total volume of open positions
   double            m_control_session_interest_inc;           // Controlled value of the total open position volume growth in the current session
   double            m_control_session_interest_dec;           // Controlled value of the total open position volume decrease in the current session
   double            m_changed_session_interest_value;         // Change value of the open positions total volume in the current session
   bool              m_is_change_session_interest_inc;         // Flag of total open positions' volume change in the current session exceeding the growth value
   bool              m_is_change_session_interest_dec;         // Flag of total open positions' volume change in the current session exceeding the decrease value
   //--- The total volume of Buy orders at the moment
   double            m_control_session_buy_ord_volume_inc;     // Controlled value of the current total buy order volume growth
   double            m_control_session_buy_ord_volume_dec;     // Controlled value of the current total buy order volume decrease
   double            m_changed_session_buy_ord_volume_value;   // Change value of the current total buy order volume
   bool              m_is_change_session_buy_ord_volume_inc;   // Flag of changing the current total buy orders volume exceeding the growth value
   bool              m_is_change_session_buy_ord_volume_dec;   // Flag of changing the current total buy orders volume exceeding the decrease value
   //--- The total volume of Sell orders at the moment
   double            m_control_session_sell_ord_volume_inc;    // Controlled value of the current total sell order volume growth
   double            m_control_session_sell_ord_volume_dec;    // Controlled value of the current total sell order volume decrease
   double            m_changed_session_sell_ord_volume_value;  // Change value of the current total sell order volume
   bool              m_is_change_session_sell_ord_volume_inc;  // Flag of changing the current total sell orders volume exceeding the growth value
   bool              m_is_change_session_sell_ord_volume_dec;  // Flag of changing the current total sell orders volume exceeding the decrease value
   //--- Session open price
   double            m_control_session_open_inc;               // Controlled value of the session open price growth
   double            m_control_session_open_dec;               // Controlled value of the session open price decrease
   double            m_changed_session_open_value;             // Session open price change value
   bool              m_is_change_session_open_inc;             // Flag of the session open price change exceeding the growth value
   bool              m_is_change_session_open_dec;             // Flag of the session open price change exceeding the decrease value
   //--- Session close price
   double            m_control_session_close_inc;              // Controlled value of the session close price growth
   double            m_control_session_close_dec;              // Controlled value of the session close price decrease
   double            m_changed_session_close_value;            // Session close price change value
   bool              m_is_change_session_close_inc;            // Flag of the session close price change exceeding the growth value
   bool              m_is_change_session_close_dec;            // Flag of the session close price change exceeding the decrease value
   //--- The average weighted session price
   double            m_control_session_aw_inc;                 // Controlled value of the average weighted session price growth
   double            m_control_session_aw_dec;                 // Controlled value of the average weighted session price decrease
   double            m_changed_session_aw_value;               // The average weighted session price change value
   bool              m_is_change_session_aw_inc;               // Flag of the average weighted session price change value exceeding the growth value
   bool              m_is_change_session_aw_dec;               // Flag of the average weighted session price change value exceeding the decrease value
   

Na seção privada declaramos os métodos virtuais (já declarados na classe base CBaseObj) de inicialização de variáveis de acompanhamento e de propriedades do símbolo controladas, também declaramos o método de verificação de alteração de propriedades que retorna o código do evento e o método que define o tipo de evento de acordo com seu código e que registra o evento na lista de eventos:

//--- Initialize the variables of (1) tracked, (2) controlled symbol data
   virtual void      InitChangesParams(void);
   virtual void      InitControlsParams(void);
//--- Check symbol changes, return a change code
   virtual int       SetEventCode(void);
//--- Set an event type and fill in the event list
   virtual void      SetTypeEvent(void);
   

Fora do corpo da classe, escrevemos imediatamente sua implementação.
Método de inicialização para propriedades de símbolo rastreadas:

//+------------------------------------------------------------------+
//| Initialize the variables of tracked symbol data                  |
//+------------------------------------------------------------------+
void CSymbol::InitChangesParams(void)
  {
//--- List and code of changes
   this.m_list_events.Clear();                           // Clear the change list
   this.m_list_events.Sort();                            // Sort the change list
//--- Execution
   this.m_is_change_trade_mode=false;                    // Flag of changing trading mode for a symbol
//--- Current session deals
   this.m_changed_session_deals_value=0;                 // Value of change in the number of deals
   this.m_is_change_session_deals_inc=false;             // Flag of a change in the number of deals exceeding the growth value
   this.m_is_change_session_deals_dec=false;             // Flag of a change in the number of deals exceeding the decrease value
//--- Buy orders of the current session
   this.m_changed_session_buy_ord_value=0;               // Buy orders change value
   this.m_is_change_session_buy_ord_inc=false;           // Flag of a change in the number of Buy orders exceeding the growth value
   this.m_is_change_session_buy_ord_dec=false;           // Flag of a change in the number of Buy orders exceeding the decrease value
//--- Sell orders of the current session
   this.m_changed_session_sell_ord_value=0;              // Sell orders change value
   this.m_is_change_session_sell_ord_inc=false;          // Flag of a change in the number of Sell orders exceeding the growth value
   this.m_is_change_session_sell_ord_dec=false;          // Flag of a change in the number of Sell orders exceeding the decrease value
//--- Volume of the last deal
   this.m_changed_volume_value=0;                        // Value of the volume change in the last deal
   this.m_is_change_volume_inc=false;                    // Flag of the volume change in the last deal exceeding the growth value
   this.m_is_change_volume_dec=false;                    // Flag of the volume change in the last deal exceeding the decrease value
//--- Maximum volume within a day
   this.m_changed_volume_high_day_value=0;               // Maximum volume change value within a day
   this.m_is_change_volume_high_day_inc=false;           // Flag of the maximum day volume exceeding the growth value
   this.m_is_change_volume_high_day_dec=false;           // Flag of the maximum day volume exceeding the decrease value
//--- Minimum volume within a day
   this.m_changed_volume_low_day_value=0;                // Minimum volume change value within a day
   this.m_is_change_volume_low_day_inc=false;            // Flag of the minimum day volume exceeding the growth value
   this.m_is_change_volume_low_day_dec=false;            // Flag of the minimum day volume exceeding the decrease value
//--- Spread
   this.m_changed_spread_value=0;                        // Spread change value in points
   this.m_is_change_spread_inc=false;                    // Flag of spread change in points exceeding the growth value
   this.m_is_change_spread_dec=false;                    // Flag of spread change in points exceeding the decrease value
//--- StopLevel
   this.m_changed_stops_level_value=0;                   // StopLevel change value in points
   this.m_is_change_stops_level_inc=false;               // Flag of StopLevel change in points exceeding the growth value
   this.m_is_change_stops_level_dec=false;               // Flag of StopLevel change in points exceeding the decrease value
//--- Freeze distance
   this.m_changed_freeze_level_value=0;                  // FreezeLevel change value in points
   this.m_is_change_freeze_level_inc=false;              // Flag of FreezeLevel change in points exceeding the growth value
   this.m_is_change_freeze_level_dec=false;              // Flag of FreezeLevel change in points exceeding the decrease value
   
//--- Bid/Last
   this.m_changed_bid_last_value=0;                      // Bid or Last price change value
   this.m_is_change_bid_last_inc=false;                  // Flag of Bid or Last price change exceeding the growth value
   this.m_is_change_bid_last_dec=false;                  // Flag of Bid or Last price change exceeding the decrease value
//--- Maximum Bid/Last of the day
   this.m_changed_bid_last_high_value=0;                 // Maximum Bid or Last change value for the day
   this.m_is_change_bid_last_high_inc=false;             // Flag of the maximum Bid or Last price change for the day exceeding the growth value
   this.m_is_change_bid_last_high_dec=false;             // Flag of the maximum Bid or Last price change for the day exceeding the decrease value
//--- Minimum Bid/Last of the day
   this.m_changed_bid_last_low_value=0;                  // Minimum Bid or Last change value for the day
   this.m_is_change_bid_last_low_inc=false;              // Flag of the minimum Bid or Last price change for the day exceeding the growth value
   this.m_is_change_bid_last_low_dec=false;              // Flag of the minimum Bid or Last price change for the day exceeding the decrease value
//--- Ask
   this.m_changed_ask_value=0;                           // Ask price change value
   this.m_is_change_ask_inc=false;                       // Flag of the Ask price change exceeding the growth value
   this.m_is_change_ask_dec=false;                       // Flag of the Ask price change exceeding the decrease value
//--- Maximum Ask price for the day
   this.m_changed_ask_high_value=0;                      // Maximum Ask price change value for the day
   this.m_is_change_ask_high_inc=false;                  // Flag of the maximum day Ask exceeding the growth value
   this.m_is_change_ask_high_dec=false;                  // Flag of the maximum day Ask exceeding the decrease value
//--- Minimum Ask price for the day
   this.m_changed_ask_low_value=0;                       // Minimum Ask price change value for the day
   this.m_is_change_ask_low_inc=false;                   // Flag of the minimum Ask volume exceeding the growth value
   this.m_is_change_ask_low_dec=false;                   // Flag of the minimum Ask volume exceeding the decrease value
//--- Real Volume for the day
   this.m_changed_volume_real_value=0;                   // Real volume change value of the day
   this.m_is_change_volume_real_inc=false;               // Flag of the real volume change for the day exceeding the growth value
   this.m_is_change_volume_real_dec=false;               // Flag of the real volume change for the day exceeding the decrease value
//--- Maximum real volume for the day
   this.m_changed_volume_high_real_day_value=0;          // Maximum real volume change value of the day
   this.m_is_change_volume_high_real_day_inc=false;      // Flag of the maximum real volume change for the day exceeding the growth value
   this.m_is_change_volume_high_real_day_dec=false;      // Flag of the maximum real volume change for the day exceeding the decrease value
//--- Minimum real volume for the day
   this.m_changed_volume_low_real_day_value=0;           // Minimum real volume change value of the day
   this.m_is_change_volume_low_real_day_inc=false;       // Flag of the minimum real volume change for the day exceeding the growth value
   this.m_is_change_volume_low_real_day_dec=false;       // Flag of the minimum real volume change for the day exceeding the decrease value
//--- Strike price
   this.m_changed_option_strike_value=0;                 // Strike price change value
   this.m_is_change_option_strike_inc=false;             // Flag of the strike price change exceeding the growth value
   this.m_is_change_option_strike_dec=false;             // Flag of the strike price change exceeding the decrease value
//--- Total volume of positions and orders
   this.m_changed_volume_limit_value=0;                  // Minimum total volume change value
   this.m_is_change_volume_limit_inc=false;              // Flag of the minimum total volume increase
   this.m_is_change_volume_limit_dec=false;              // Flag of the minimum total volume decrease
//---  Swap long
   this.m_changed_swap_long_value=0;                     // Swap long change value
   this.m_is_change_swap_long_inc=false;                 // Flag of the swap long increase
   this.m_is_change_swap_long_dec=false;                 // Flag of the swap long decrease
//---  Swap short
   this.m_changed_swap_short_value=0;                    // Swap short change value
   this.m_is_change_swap_short_inc=false;                // Flag of the swap short increase
   this.m_is_change_swap_short_dec=false;                // Flag of the swap short decrease
//--- The total volume of deals in the current session
   this.m_changed_session_volume_value=0;                // The total deal volume change value in the current session
   this.m_is_change_session_volume_inc=false;            // Flag of total trade volume change in the current session exceeding the growth value
   this.m_is_change_session_volume_dec=false;            // Flag of total trade volume change in the current session exceeding the decrease value
//--- The total turnover in the current session
   this.m_changed_session_turnover_value=0;              // Total turnover change value in the current session
   this.m_is_change_session_turnover_inc=false;          // Flag of total turnover change in the current session exceeding the growth value
   this.m_is_change_session_turnover_dec=false;          // Flag of total turnover change in the current session exceeding the decrease value
//--- The total volume of open positions
   this.m_changed_session_interest_value=0;              // Change value of the open positions total volume in the current session
   this.m_is_change_session_interest_inc=false;          // Flag of total open positions' volume change in the current session exceeding the growth value
   this.m_is_change_session_interest_dec=false;          // Flag of total open positions' volume change in the current session exceeding the decrease value
//--- The total volume of Buy orders at the moment
   this.m_changed_session_buy_ord_volume_value=0;        // Change value of the current total buy order volume
   this.m_is_change_session_buy_ord_volume_inc=false;    // Flag of changing the current total buy orders volume exceeding the growth value
   this.m_is_change_session_buy_ord_volume_dec=false;    // Flag of changing the current total buy orders volume exceeding the decrease value
//--- The total volume of Sell orders at the moment
   this.m_changed_session_sell_ord_volume_value=0;       // Change value of the current total sell order volume
   this.m_is_change_session_sell_ord_volume_inc=false;   // Flag of changing the current total sell orders volume exceeding the growth value
   this.m_is_change_session_sell_ord_volume_dec=false;   // Flag of changing the current total sell orders volume exceeding the decrease value
//--- Session open price
   this.m_changed_session_open_value=0;                  // Session open price change value
   this.m_is_change_session_open_inc=false;              // Flag of the session open price change exceeding the growth value
   this.m_is_change_session_open_dec=false;              // Flag of the session open price change exceeding the decrease value
//--- Session close price
   this.m_changed_session_close_value=0;                 // Session close price change value
   this.m_is_change_session_close_inc=false;             // Flag of the session close price change exceeding the growth value
   this.m_is_change_session_close_dec=false;             // Flag of the session close price change exceeding the decrease value
//--- The average weighted session price
   this.m_changed_session_aw_value=0;                    // The average weighted session price change value
   this.m_is_change_session_aw_inc=false;                // Flag of the average weighted session price change value exceeding the growth value
   this.m_is_change_session_aw_dec=false;                // Flag of the average weighted session price change value exceeding the decrease value
  }
//+------------------------------------------------------------------+


No método, os valores iniciais simplesmente são atribuídos às variáveis das propriedades de símbolo rastreadas, declaradas anteriormente na seção privada da classe.

Método de inicialização para valores controlados das propriedades do símbolo:

//+------------------------------------------------------------------+
//| Initialize the variables of controlled symbol data               |
//+------------------------------------------------------------------+
void CSymbol::InitControlsParams(void)
  {
//--- Current session deals
   this.m_control_session_deals_inc=10;                  // Controlled value of the growth of the number of deals
   this.m_control_session_deals_dec=10;                  // Controlled value of the decrease in the number of deals
//--- Buy orders of the current session
   this.m_control_session_buy_ord_inc=10;                // Controlled value of the growth of the number of Buy orders
   this.m_control_session_buy_ord_dec=10;                // Controlled value of the decrease in the number of Buy orders
//--- Sell orders of the current session
   this.m_control_session_sell_ord_inc=10;               // Controlled value of the growth of the number of Sell orders
   this.m_control_session_sell_ord_dec=10;               // Controlled value of the decrease in the number of Sell orders
//--- Volume of the last deal
   this.m_control_volume_inc=10;                         // Controlled value of the volume growth in the last deal
   this.m_control_volume_dec=10;                         // Controlled value of the volume decrease in the last deal
//--- Maximum volume within a day
   this.m_control_volume_high_day_inc=50;                // Controlled value of the maximum volume growth for a day
   this.m_control_volume_high_day_dec=50;                // Controlled value of the maximum volume decrease for a day
//--- Minimum volume within a day
   this.m_control_volume_low_day_inc=50;                 // Controlled value of the minimum volume growth for a day
   this.m_control_volume_low_day_dec=50;                 // Controlled value of the minimum volume decrease for a day
//--- Spread
   this.m_control_spread_inc=2;                          // Controlled spread growth value in points
   this.m_control_spread_dec=2;                          // Controlled spread decrease value in points
//--- StopLevel
   this.m_control_stops_level_inc=2;                     // Controlled StopLevel growth value in points
   this.m_control_stops_level_dec=2;                     // Controlled StopLevel decrease value in points
//--- Freeze distance
   this.m_control_freeze_level_inc=2;                    // Controlled FreezeLevel growth value in points
   this.m_control_freeze_level_dec=2;                    // Controlled FreezeLevel decrease value in points
   
//--- Bid/Last
   this.m_control_bid_last_inc=DBL_MAX;                  // Controlled value of Bid or Last price growth
   this.m_control_bid_last_dec=DBL_MAX;                  // Controlled value of Bid or Last price decrease
//--- Maximum Bid/Last of the day
   this.m_control_bid_last_high_inc=DBL_MAX;             // Controlled growth value of the maximum Bid or Last price of the day
   this.m_control_bid_last_high_dec=DBL_MAX;             // Controlled decrease value of the maximum Bid or Last price of the day
//--- Minimum Bid/Last of the day
   this.m_control_bid_last_low_inc=DBL_MAX;              // Controlled growth value of the minimum Bid or Last price of the day
   this.m_control_bid_last_low_dec=DBL_MAX;              // Controlled decrease value of the minimum Bid or Last price of the day
//--- Ask
   this.m_control_ask_inc=DBL_MAX;                       // Controlled value of the Ask price growth
   this.m_control_ask_dec=DBL_MAX;                       // Controlled value of the Ask price decrease
//--- Maximum Ask price for the day
   this.m_control_ask_high_inc=DBL_MAX;                  // Controlled growth value of the maximum Ask price of the day
   this.m_control_ask_high_dec=DBL_MAX;                  // Controlled decrease value of the maximum Ask price of the day
//--- Minimum Ask price for the day
   this.m_control_ask_low_inc=DBL_MAX;                   // Controlled growth value of the minimum Ask price of the day
   this.m_control_ask_low_dec=DBL_MAX;                   // Controlled decrease value of the minimum Ask price of the day
//--- Real Volume for the day
   this.m_control_volume_real_inc=50;                    // Controlled value of the real volume growth of the day
   this.m_control_volume_real_dec=50;                    // Controlled value of the real volume decrease of the day
//--- Maximum real volume for the day
   this.m_control_volume_high_real_day_inc=20;           // Controlled value of the maximum real volume growth of the day
   this.m_control_volume_high_real_day_dec=20;           // Controlled value of the maximum real volume decrease of the day
//--- Minimum real volume for the day
   this.m_control_volume_low_real_day_inc=10;            // Controlled value of the minimum real volume growth of the day
   this.m_control_volume_low_real_day_dec=10;            // Controlled value of the minimum real volume decrease of the day
//--- Strike price
   this.m_control_option_strike_inc=0;                   // Controlled value of the strike price growth
   this.m_control_option_strike_dec=0;                   // Controlled value of the strike price decrease
//--- The total volume of deals in the current session
   this.m_control_session_volume_inc=10;                 // Controlled value of the total trade volume growth in the current session
   this.m_control_session_volume_dec=10;                 // Controlled value of the total trade volume decrease in the current session
//--- The total turnover in the current session
   this.m_control_session_turnover_inc=1000;             // Controlled value of the total turnover growth in the current session
   this.m_control_session_turnover_dec=500;              // Controlled value of the total turnover decrease in the current session
//--- The total volume of open positions
   this.m_control_session_interest_inc=50;               // Controlled value of the total open position volume growth in the current session
   this.m_control_session_interest_dec=20;               // Controlled value of the total open position volume decrease in the current session
//--- The total volume of Buy orders at the moment
   this.m_control_session_buy_ord_volume_inc=50;         // Controlled value of the current total buy order volume growth
   this.m_control_session_buy_ord_volume_dec=20;         // Controlled value of the current total buy order volume decrease
//--- The total volume of Sell orders at the moment
   this.m_control_session_sell_ord_volume_inc=50;        // Controlled value of the current total sell order volume growth
   this.m_control_session_sell_ord_volume_dec=20;        // Controlled value of the current total sell order volume decrease
//--- Session open price
   this.m_control_session_open_inc=0;                    // Controlled value of the session open price growth
   this.m_control_session_open_dec=0;                    // Controlled value of the session open price decrease
//--- Session close price
   this.m_control_session_close_inc=0;                   // Controlled value of the session close price growth
   this.m_control_session_close_dec=0;                   // Controlled value of the session close price decrease
//--- The average weighted session price
   this.m_control_session_aw_inc=0;                      // Controlled value of the average weighted session price growth
   this.m_control_session_aw_dec=0;                      // Controlled value of the average weighted session price decrease
  }
//+------------------------------------------------------------------+

No método, os valores iniciais simplesmente são atribuídos às variáveis das propriedades controladas do símbolo, declaradas anteriormente na seção privada da classe. Se as propriedades excederem os valores inseridos nestas variáveis, será gerado o evento de conta correspondente. Para desativar o controle de propriedade, um valor DBL_MAX deve ser atribuído à sua variável. Para rastrear alterações em qualquer valor, é necessário definir a variável como 0.

Método que verifica a alteração nas propriedades do símbolo e que retorna seu código:

//+------------------------------------------------------------------+
//| Check symbol changes, return a change code                       |
//+------------------------------------------------------------------+
int CSymbol::SetEventCode(void)
  {
   this.m_event_code=SYMBOL_EVENT_FLAG_NO_EVENT;

   if(this.m_struct_curr_symbol.trade_mode!=this.m_struct_prev_symbol.trade_mode)
      this.m_event_code+=SYMBOL_EVENT_FLAG_TRADE_MODE;
   if(this.m_struct_curr_symbol.session_deals!=this.m_struct_prev_symbol.session_deals)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_DEALS;
   if(this.m_struct_curr_symbol.session_buy_orders!=this.m_struct_prev_symbol.session_buy_orders)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_BUY_ORDERS;
   if(this.m_struct_curr_symbol.session_sell_orders!=this.m_struct_prev_symbol.session_sell_orders)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_SELL_ORDERS;
   if(this.m_struct_curr_symbol.volume!=this.m_struct_prev_symbol.volume)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME;
   if(this.m_struct_curr_symbol.volume_high_day!=this.m_struct_prev_symbol.volume_high_day)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME_HIGH_DAY;
   if(this.m_struct_curr_symbol.volume_low_day!=this.m_struct_prev_symbol.volume_low_day)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME_LOW_DAY;
   if(this.m_struct_curr_symbol.spread!=this.m_struct_prev_symbol.spread)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SPREAD;
   if(this.m_struct_curr_symbol.stops_level!=this.m_struct_prev_symbol.stops_level)
      this.m_event_code+=SYMBOL_EVENT_FLAG_STOPLEVEL;
   if(this.m_struct_curr_symbol.freeze_level!=this.m_struct_prev_symbol.freeze_level)
      this.m_event_code+=SYMBOL_EVENT_FLAG_FREEZELEVEL;

   if(this.m_struct_curr_symbol.bid_last!=this.m_struct_prev_symbol.bid_last)
      this.m_event_code+=SYMBOL_EVENT_FLAG_BID_LAST;
   if(this.m_struct_curr_symbol.bid_last_high!=this.m_struct_prev_symbol.bid_last_high)
      this.m_event_code+=SYMBOL_EVENT_FLAG_BID_LAST_HIGH;
   if(this.m_struct_curr_symbol.bid_last_low!=this.m_struct_prev_symbol.bid_last_low)
      this.m_event_code+=SYMBOL_EVENT_FLAG_BID_LAST_LOW;
   if(this.m_struct_curr_symbol.ask!=this.m_struct_prev_symbol.ask)
      this.m_event_code+=SYMBOL_EVENT_FLAG_ASK;
   if(this.m_struct_curr_symbol.ask_high!=this.m_struct_prev_symbol.ask_high)
      this.m_event_code+=SYMBOL_EVENT_FLAG_ASK_HIGH;
   if(this.m_struct_curr_symbol.ask_low!=this.m_struct_prev_symbol.ask_low)
      this.m_event_code+=SYMBOL_EVENT_FLAG_ASK_LOW;
   if(this.m_struct_curr_symbol.volume_real_day!=this.m_struct_prev_symbol.volume_real_day)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME_REAL_DAY;
   if(this.m_struct_curr_symbol.volume_high_real_day!=this.m_struct_prev_symbol.volume_high_real_day)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME_HIGH_REAL_DAY;
   if(this.m_struct_curr_symbol.volume_low_real_day!=this.m_struct_prev_symbol.volume_low_real_day)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME_LOW_REAL_DAY;
   if(this.m_struct_curr_symbol.option_strike!=this.m_struct_prev_symbol.option_strike)
      this.m_event_code+=SYMBOL_EVENT_FLAG_OPTION_STRIKE;
   if(this.m_struct_curr_symbol.volume_limit!=this.m_struct_prev_symbol.volume_limit)
      this.m_event_code+=SYMBOL_EVENT_FLAG_VOLUME_LIMIT;
   if(this.m_struct_curr_symbol.swap_long!=this.m_struct_prev_symbol.swap_long)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SWAP_LONG;
   if(this.m_struct_curr_symbol.swap_short!=this.m_struct_prev_symbol.swap_short)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SWAP_SHORT;
   if(this.m_struct_curr_symbol.session_volume!=this.m_struct_prev_symbol.session_volume)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_VOLUME;
   if(this.m_struct_curr_symbol.session_turnover!=this.m_struct_prev_symbol.session_turnover)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_TURNOVER;
   if(this.m_struct_curr_symbol.session_interest!=this.m_struct_prev_symbol.session_interest)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_INTEREST;
   if(this.m_struct_curr_symbol.session_buy_ord_volume!=this.m_struct_prev_symbol.session_buy_ord_volume)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_BUY_ORD_VOLUME;
   if(this.m_struct_curr_symbol.session_sell_ord_volume!=this.m_struct_prev_symbol.session_sell_ord_volume)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_SELL_ORD_VOLUME;
   if(this.m_struct_curr_symbol.session_open!=this.m_struct_prev_symbol.session_open)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_OPEN;
   if(this.m_struct_curr_symbol.session_close!=this.m_struct_prev_symbol.session_close)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_CLOSE;
   if(this.m_struct_curr_symbol.session_aw!=this.m_struct_prev_symbol.session_aw)
      this.m_event_code+=SYMBOL_EVENT_FLAG_SESSION_AW;
//---
   return this.m_event_code;
  }
//+------------------------------------------------------------------+

No método primeiro é redefinido o código de evento, depois, são comparados os valores dos parâmetros controlados do símbolo na estrutura de dados atual e na estrutura de dados anterior. Se os dados não forem iguais, ao código do evento é adicionado o sinalizador correspondente.

Método que define o tipo de evento e registra o evento na lista de eventos:

//+------------------------------------------------------------------+
//| Set a symbol object event type                                   |
//+------------------------------------------------------------------+
void CSymbol::SetTypeEvent(void)
  {
   this.InitChangesParams();
   ENUM_SYMBOL_EVENT event_id=SYMBOL_EVENT_NO_EVENT;
//--- Change of trading modes on a symbol
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_TRADE_MODE))
     {
      event_id=
        (
         this.TradeMode()==SYMBOL_TRADE_MODE_DISABLED  ? SYMBOL_EVENT_TRADE_DISABLE    :
         this.TradeMode()==SYMBOL_TRADE_MODE_LONGONLY  ? SYMBOL_EVENT_TRADE_LONGONLY   :
         this.TradeMode()==SYMBOL_TRADE_MODE_SHORTONLY ? SYMBOL_EVENT_TRADE_SHORTONLY  :
         this.TradeMode()==SYMBOL_TRADE_MODE_CLOSEONLY ? SYMBOL_EVENT_TRADE_CLOSEONLY  :
         SYMBOL_EVENT_TRADE_FULL
        );
      this.m_is_change_trade_mode=true;
      if(this.EventAdd(event_id,this.TickTime(),this.TradeMode(),this.Name()))
         this.m_struct_prev_symbol.trade_mode=this.m_struct_curr_symbol.trade_mode;
     }
//--- Change of the number of deals in the current session
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_DEALS))
     {
      this.m_changed_session_deals_value=this.m_struct_curr_symbol.session_deals-this.m_struct_prev_symbol.session_deals;
      if(this.m_changed_session_deals_value>this.m_control_session_deals_inc)
        {
         this.m_is_change_session_deals_inc=true;
         event_id=SYMBOL_EVENT_SESSION_DEALS_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_deals_value,this.Name()))
            this.m_struct_prev_symbol.session_deals=this.m_struct_curr_symbol.session_deals;
        }
      else if(this.m_changed_session_deals_value<-this.m_control_session_deals_dec)
        {
         this.m_is_change_session_deals_dec=true;
         event_id=SYMBOL_EVENT_SESSION_DEALS_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_deals_value,this.Name()))
            this.m_struct_prev_symbol.session_deals=this.m_struct_curr_symbol.session_deals;
        }
     }
//--- Change of the total number of the current buy orders
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_BUY_ORDERS))
     {
      this.m_changed_session_buy_ord_value=this.m_struct_curr_symbol.session_buy_orders-this.m_struct_prev_symbol.session_buy_orders;
      if(this.m_changed_session_buy_ord_value>this.m_control_session_buy_ord_inc)
        {
         this.m_is_change_session_buy_ord_inc=true;
         event_id=SYMBOL_EVENT_SESSION_BUY_ORDERS_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_buy_ord_value,this.Name()))
            this.m_struct_prev_symbol.session_buy_orders=this.m_struct_curr_symbol.session_buy_orders;
        }
      else if(this.m_changed_session_buy_ord_value<-this.m_control_session_buy_ord_dec)
        {
         this.m_is_change_session_buy_ord_dec=true;
         event_id=SYMBOL_EVENT_SESSION_BUY_ORDERS_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_buy_ord_value,this.Name()))
            this.m_struct_prev_symbol.session_buy_orders=this.m_struct_curr_symbol.session_buy_orders;
        }
     }
//--- Change of the total number of the current sell orders
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_SELL_ORDERS))
     {
      this.m_changed_session_sell_ord_value=this.m_struct_curr_symbol.session_sell_orders-this.m_struct_prev_symbol.session_sell_orders;
      if(this.m_changed_session_sell_ord_value>this.m_control_session_sell_ord_inc)
        {
         this.m_is_change_session_sell_ord_inc=true;
         event_id=SYMBOL_EVENT_SESSION_SELL_ORDERS_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_sell_ord_value,this.Name()))
            this.m_struct_prev_symbol.session_sell_orders=this.m_struct_curr_symbol.session_sell_orders;
        }
      else if(this.m_changed_session_sell_ord_value<-this.m_control_session_sell_ord_dec)
        {
         this.m_is_change_session_sell_ord_dec=true;
         event_id=SYMBOL_EVENT_SESSION_SELL_ORDERS_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_sell_ord_value,this.Name()))
            this.m_struct_prev_symbol.session_sell_orders=this.m_struct_curr_symbol.session_sell_orders;
        }
     }
//--- Volume change in the last deal
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME))
     {
      this.m_changed_volume_value=this.m_struct_curr_symbol.volume-this.m_struct_prev_symbol.volume;
      if(this.m_changed_volume_value>this.m_control_volume_inc)
        {
         this.m_is_change_volume_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_value,this.Name()))
            this.m_struct_prev_symbol.volume=this.m_struct_curr_symbol.volume;
        }
      else if(this.m_changed_volume_value<-this.m_control_volume_dec)
        {
         this.m_is_change_volume_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_value,this.Name()))
            this.m_struct_prev_symbol.volume=this.m_struct_curr_symbol.volume;
        }
     }
//--- Maximum volume change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME_HIGH_DAY))
     {
      this.m_changed_volume_high_day_value=this.m_struct_curr_symbol.volume_high_day-this.m_struct_prev_symbol.volume_high_day;
      if(this.m_changed_volume_high_day_value>this.m_control_volume_high_day_inc)
        {
         this.m_is_change_volume_high_day_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_HIGH_DAY_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_high_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_high_day=this.m_struct_curr_symbol.volume_high_day;
        }
      else if(this.m_changed_volume_high_day_value<-this.m_control_volume_high_day_dec)
        {
         this.m_is_change_volume_high_day_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_HIGH_DAY_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_high_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_high_day=this.m_struct_curr_symbol.volume_high_day;
        }
     }
//--- Minimum volume change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME_LOW_DAY))
     {
      this.m_changed_volume_low_day_value=this.m_struct_curr_symbol.volume_low_day-this.m_struct_prev_symbol.volume_low_day;
      if(this.m_changed_volume_low_day_value>this.m_control_volume_low_day_inc)
        {
         this.m_is_change_volume_low_day_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_LOW_DAY_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_low_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_low_day=this.m_struct_curr_symbol.volume_low_day;
        }
      else if(this.m_changed_volume_low_day_value<-this.m_control_volume_low_day_dec)
        {
         this.m_is_change_volume_low_day_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_LOW_DAY_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_low_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_low_day=this.m_struct_curr_symbol.volume_low_day;
        }
     }
//--- Spread value change in points
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SPREAD))
     {
      this.m_changed_spread_value=this.m_struct_curr_symbol.spread-this.m_struct_prev_symbol.spread;
      if(this.m_changed_spread_value>this.m_control_spread_inc)
        {
         this.m_is_change_spread_inc=true;
         event_id=SYMBOL_EVENT_SPREAD_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_spread_value,this.Name()))
            this.m_struct_prev_symbol.spread=this.m_struct_curr_symbol.spread;
        }
      else if(this.m_changed_spread_value<-this.m_control_spread_dec)
        {
         this.m_is_change_spread_dec=true;
         event_id=SYMBOL_EVENT_SPREAD_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_spread_value,this.Name()))
            this.m_struct_prev_symbol.spread=this.m_struct_curr_symbol.spread;
        }
     }
//--- StopLevel change in points
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_STOPLEVEL))
     {
      this.m_changed_stops_level_value=this.m_struct_curr_symbol.stops_level-this.m_struct_prev_symbol.stops_level;
      if(this.m_changed_stops_level_value>this.m_control_stops_level_inc)
        {
         this.m_is_change_stops_level_inc=true;
         event_id=SYMBOL_EVENT_STOPLEVEL_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_stops_level_value,this.Name()))
            this.m_struct_prev_symbol.stops_level=this.m_struct_curr_symbol.stops_level;
        }
      else if(this.m_changed_stops_level_value<-this.m_control_stops_level_dec)
        {
         this.m_is_change_stops_level_dec=true;
         event_id=SYMBOL_EVENT_STOPLEVEL_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_stops_level_value,this.Name()))
            this.m_struct_prev_symbol.stops_level=this.m_struct_curr_symbol.stops_level;
        }
     }
//--- FreezeLevel change in points
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_FREEZELEVEL))
     {
      this.m_changed_freeze_level_value=this.m_struct_curr_symbol.freeze_level-this.m_struct_prev_symbol.freeze_level;
      if(this.m_changed_freeze_level_value>this.m_control_freeze_level_inc)
        {
         this.m_is_change_freeze_level_inc=true;
         event_id=SYMBOL_EVENT_FREEZELEVEL_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_freeze_level_value,this.Name()))
            this.m_struct_prev_symbol.freeze_level=this.m_struct_curr_symbol.freeze_level;
        }
      else if(this.m_changed_freeze_level_value<-this.m_control_freeze_level_dec)
        {
         this.m_is_change_freeze_level_dec=true;
         event_id=SYMBOL_EVENT_FREEZELEVEL_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_freeze_level_value,this.Name()))
            this.m_struct_prev_symbol.freeze_level=this.m_struct_curr_symbol.freeze_level;
        }
     }
//--- Bid/Last price change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_BID_LAST))
     {
      this.m_changed_bid_last_value=this.m_struct_curr_symbol.bid_last-this.m_struct_prev_symbol.bid_last;
      if(this.m_changed_bid_last_value>this.m_control_bid_last_inc)
        {
         this.m_is_change_bid_last_inc=true;
         event_id=SYMBOL_EVENT_BID_LAST_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_bid_last_value,this.Name()))
            this.m_struct_prev_symbol.bid_last=this.m_struct_curr_symbol.bid_last;
        }
      else if(this.m_changed_bid_last_value<-this.m_control_bid_last_dec)
        {
         this.m_is_change_bid_last_dec=true;
         event_id=SYMBOL_EVENT_BID_LAST_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_bid_last_value,this.Name()))
            this.m_struct_prev_symbol.bid_last=this.m_struct_curr_symbol.bid_last;
        }
     }
//--- Maximum Bid/Last change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_BID_LAST_HIGH))
     {
      this.m_changed_bid_last_high_value=this.m_struct_curr_symbol.bid_last_high-this.m_struct_prev_symbol.bid_last_high;
      if(this.m_changed_bid_last_high_value>this.m_control_bid_last_high_inc)
        {
         this.m_is_change_bid_last_high_inc=true;
         event_id=SYMBOL_EVENT_BID_LAST_HIGH_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_bid_last_high_value,this.Name()))
            this.m_struct_prev_symbol.bid_last_high=this.m_struct_curr_symbol.bid_last_high;
        }
      else if(this.m_changed_bid_last_high_value<-this.m_control_bid_last_high_dec)
        {
         this.m_is_change_bid_last_high_dec=true;
         event_id=SYMBOL_EVENT_BID_LAST_HIGH_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_bid_last_high_value,this.Name()))
            this.m_struct_prev_symbol.bid_last_high=this.m_struct_curr_symbol.bid_last_high;
        }
     }
//--- Minimum Bid/Last change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_BID_LAST_LOW))
     {
      this.m_changed_bid_last_low_value=this.m_struct_curr_symbol.bid_last_low-this.m_struct_prev_symbol.bid_last_low;
      if(this.m_changed_bid_last_low_value>this.m_control_bid_last_low_inc)
        {
         this.m_is_change_bid_last_low_inc=true;
         event_id=SYMBOL_EVENT_BID_LAST_LOW_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_bid_last_low_value,this.Name()))
            this.m_struct_prev_symbol.bid_last_low=this.m_struct_curr_symbol.bid_last_low;
        }
      else if(this.m_changed_bid_last_low_value<-this.m_control_bid_last_low_dec)
        {
         this.m_is_change_bid_last_low_dec=true;
         event_id=SYMBOL_EVENT_BID_LAST_LOW_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_bid_last_low_value,this.Name()))
            this.m_struct_prev_symbol.bid_last_low=this.m_struct_curr_symbol.bid_last_low;
        }
     }
//--- Ask price change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_ASK))
     {
      this.m_changed_ask_value=this.m_struct_curr_symbol.ask-this.m_struct_prev_symbol.ask;
      if(this.m_changed_ask_value>this.m_control_ask_inc)
        {
         this.m_is_change_ask_inc=true;
         event_id=SYMBOL_EVENT_ASK_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_ask_value,this.Name()))
            this.m_struct_prev_symbol.ask=this.m_struct_curr_symbol.ask;
        }
      else if(this.m_changed_ask_value<-this.m_control_ask_dec)
        {
         this.m_is_change_ask_dec=true;
         event_id=SYMBOL_EVENT_ASK_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_ask_value,this.Name()))
            this.m_struct_prev_symbol.ask=this.m_struct_curr_symbol.ask;
        }
     }
//--- Maximum As change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_ASK_HIGH))
     {
      this.m_changed_ask_high_value=this.m_struct_curr_symbol.ask_high-this.m_struct_prev_symbol.ask_high;
      if(this.m_changed_ask_high_value>this.m_control_ask_high_inc)
        {
         this.m_is_change_ask_high_inc=true;
         event_id=SYMBOL_EVENT_ASK_HIGH_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_ask_high_value,this.Name()))
            this.m_struct_prev_symbol.ask_high=this.m_struct_curr_symbol.ask_high;
        }
      else if(this.m_changed_ask_high_value<-this.m_control_ask_high_dec)
        {
         this.m_is_change_ask_high_dec=true;
         event_id=SYMBOL_EVENT_ASK_HIGH_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_ask_high_value,this.Name()))
            this.m_struct_prev_symbol.ask_high=this.m_struct_curr_symbol.ask_high;
        }
     }
//--- Minimum Ask change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_ASK_LOW))
     {
      this.m_changed_ask_low_value=this.m_struct_curr_symbol.ask_low-this.m_struct_prev_symbol.ask_low;
      if(this.m_changed_ask_low_value>this.m_control_ask_low_inc)
        {
         this.m_is_change_ask_low_inc=true;
         event_id=SYMBOL_EVENT_ASK_LOW_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_ask_low_value,this.Name()))
            this.m_struct_prev_symbol.ask_low=this.m_struct_curr_symbol.ask_low;
        }
      else if(this.m_changed_ask_low_value<-this.m_control_ask_low_dec)
        {
         this.m_is_change_ask_low_dec=true;
         event_id=SYMBOL_EVENT_ASK_LOW_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_ask_low_value,this.Name()))
            this.m_struct_prev_symbol.ask_low=this.m_struct_curr_symbol.ask_low;
        }
     }
//--- Real volume change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME_REAL_DAY))
     {
      this.m_changed_volume_real_value=this.m_struct_curr_symbol.volume_real_day-this.m_struct_prev_symbol.volume_real_day;
      if(this.m_changed_volume_real_value>this.m_control_volume_real_inc)
        {
         this.m_is_change_volume_real_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_REAL_DAY_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_real_value,this.Name()))
            this.m_struct_prev_symbol.volume_real_day=this.m_struct_curr_symbol.volume_real_day;
        }
      else if(this.m_changed_volume_real_value<-this.m_control_volume_real_dec)
        {
         this.m_is_change_volume_real_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_REAL_DAY_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_real_value,this.Name()))
            this.m_struct_prev_symbol.volume_real_day=this.m_struct_curr_symbol.volume_real_day;
        }
     }
//--- Maximum real volume change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME_HIGH_REAL_DAY))
     {
      this.m_changed_volume_high_real_day_value=this.m_struct_curr_symbol.volume_high_real_day-this.m_struct_prev_symbol.volume_high_real_day;
      if(this.m_changed_volume_high_real_day_value>this.m_control_volume_high_real_day_inc)
        {
         this.m_is_change_volume_high_real_day_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_HIGH_REAL_DAY_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_high_real_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_high_real_day=this.m_struct_curr_symbol.volume_high_real_day;
        }
      else if(this.m_changed_volume_high_real_day_value<-this.m_control_volume_high_real_day_dec)
        {
         this.m_is_change_volume_high_real_day_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_HIGH_REAL_DAY_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_high_real_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_high_real_day=this.m_struct_curr_symbol.volume_high_real_day;
        }
     }
//--- Minimum real volume change for a day
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME_LOW_REAL_DAY))
     {
      this.m_changed_volume_low_real_day_value=this.m_struct_curr_symbol.volume_low_real_day-this.m_struct_prev_symbol.volume_low_real_day;
      if(this.m_changed_volume_low_real_day_value>this.m_control_volume_low_real_day_inc)
        {
         this.m_is_change_volume_low_real_day_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_LOW_REAL_DAY_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_low_real_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_low_real_day=this.m_struct_curr_symbol.volume_low_real_day;
        }
      else if(this.m_changed_volume_low_real_day_value<-this.m_control_volume_low_real_day_dec)
        {
         this.m_is_change_volume_low_real_day_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_LOW_REAL_DAY_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_low_real_day_value,this.Name()))
            this.m_struct_prev_symbol.volume_low_real_day=this.m_struct_curr_symbol.volume_low_real_day;
        }
     }
//--- Strike price change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_OPTION_STRIKE))
     {
      this.m_changed_option_strike_value=this.m_struct_curr_symbol.option_strike-this.m_struct_prev_symbol.option_strike;
      if(this.m_changed_option_strike_value>this.m_control_option_strike_inc)
        {
         this.m_is_change_option_strike_inc=true;
         event_id=SYMBOL_EVENT_OPTION_STRIKE_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_option_strike_value,this.Name()))
            this.m_struct_prev_symbol.option_strike=this.m_struct_curr_symbol.option_strike;
        }
      else if(this.m_changed_option_strike_value<-this.m_control_option_strike_dec)
        {
         this.m_is_change_option_strike_dec=true;
         event_id=SYMBOL_EVENT_OPTION_STRIKE_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_option_strike_value,this.Name()))
            this.m_struct_prev_symbol.option_strike=this.m_struct_curr_symbol.option_strike;
        }
     }
//--- Change of the maximum available total position volume and pending orders in one direction
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_VOLUME_LIMIT))
     {
      this.m_changed_volume_limit_value=this.m_struct_curr_symbol.volume_limit-this.m_struct_prev_symbol.volume_limit;
      if(this.m_changed_volume_limit_value>0)
        {
         this.m_is_change_volume_limit_inc=true;
         event_id=SYMBOL_EVENT_VOLUME_LIMIT_INC;
        }
      else
        {
         this.m_is_change_volume_limit_dec=true;
         event_id=SYMBOL_EVENT_VOLUME_LIMIT_DEC;
        }
      if(this.EventAdd(event_id,this.TickTime(),this.m_changed_volume_limit_value,this.Name()))
         this.m_struct_prev_symbol.volume_limit=this.m_struct_curr_symbol.volume_limit;
     }
//--- Swap long change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SWAP_LONG))
     {
      this.m_changed_swap_long_value=this.m_struct_curr_symbol.swap_long-this.m_struct_prev_symbol.swap_long;
      if(this.m_changed_swap_long_value>0)
        {
         this.m_is_change_swap_long_inc=true;
         event_id=SYMBOL_EVENT_SWAP_LONG_INC;
        }
      else
        {
         this.m_is_change_swap_long_dec=true;
         event_id=SYMBOL_EVENT_SWAP_LONG_DEC;
        }
      if(this.EventAdd(event_id,this.TickTime(),this.m_changed_swap_long_value,this.Name()))
         this.m_struct_prev_symbol.swap_long=this.m_struct_curr_symbol.swap_long;
     }
//--- Swap short change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SWAP_SHORT))
     {
      this.m_changed_swap_short_value=this.m_struct_curr_symbol.swap_short-this.m_struct_prev_symbol.swap_short;
      if(this.m_changed_swap_short_value>0)
        {
         this.m_is_change_swap_short_inc=true;
         event_id=SYMBOL_EVENT_SWAP_SHORT_INC;
        }
      else
        {
         this.m_is_change_swap_short_dec=true;
         event_id=SYMBOL_EVENT_SWAP_SHORT_DEC;
        }
      if(this.EventAdd(event_id,this.TickTime(),this.m_changed_swap_short_value,this.Name()))
         this.m_struct_prev_symbol.swap_short=this.m_struct_curr_symbol.swap_short;
     }
//--- Change of the total volume of deals during the current session
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_VOLUME))
     {
      this.m_changed_session_volume_value=this.m_struct_curr_symbol.session_volume-this.m_struct_prev_symbol.session_volume;
      if(this.m_changed_session_volume_value>this.m_control_session_volume_inc)
        {
         this.m_is_change_session_volume_inc=true;
         event_id=SYMBOL_EVENT_SESSION_VOLUME_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_volume_value,this.Name()))
            this.m_struct_prev_symbol.session_volume=this.m_struct_curr_symbol.session_volume;
        }
      else if(this.m_changed_session_volume_value<-this.m_control_session_volume_dec)
        {
         this.m_is_change_session_volume_dec=true;
         event_id=SYMBOL_EVENT_SESSION_VOLUME_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_volume_value,this.Name()))
            this.m_struct_prev_symbol.session_volume=this.m_struct_curr_symbol.session_volume;
        }
     }
//--- Change of the total turnover during the current session
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_TURNOVER))
     {
      this.m_changed_session_turnover_value=this.m_struct_curr_symbol.session_turnover-this.m_struct_prev_symbol.session_turnover;
      if(this.m_changed_session_turnover_value>this.m_control_session_turnover_inc)
        {
         this.m_is_change_session_turnover_inc=true;
         event_id=SYMBOL_EVENT_SESSION_TURNOVER_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_turnover_value,this.Name()))
            this.m_struct_prev_symbol.session_turnover=this.m_struct_curr_symbol.session_turnover;
        }
      else if(this.m_changed_session_turnover_value<-this.m_control_session_turnover_dec)
        {
         this.m_is_change_session_turnover_dec=true;
         event_id=SYMBOL_EVENT_SESSION_TURNOVER_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_turnover_value,this.Name()))
            this.m_struct_prev_symbol.session_turnover=this.m_struct_curr_symbol.session_turnover;
        }
     }
//--- Change of the total volume of open positions during the current session
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_INTEREST))
     {
      this.m_changed_session_interest_value=this.m_struct_curr_symbol.session_interest-this.m_struct_prev_symbol.session_interest;
      if(this.m_changed_session_interest_value>this.m_control_session_interest_inc)
        {
         this.m_is_change_session_interest_inc=true;
         event_id=SYMBOL_EVENT_SESSION_INTEREST_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_interest_value,this.Name()))
            this.m_struct_prev_symbol.session_interest=this.m_struct_curr_symbol.session_interest;
        }
      else if(this.m_changed_session_interest_value<-this.m_control_session_interest_dec)
        {
         this.m_is_change_session_interest_dec=true;
         event_id=SYMBOL_EVENT_SESSION_INTEREST_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_interest_value,this.Name()))
            this.m_struct_prev_symbol.session_interest=this.m_struct_curr_symbol.session_interest;
        }
     }
//--- Change of the current total volume of buy orders
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_BUY_ORD_VOLUME))
     {
      this.m_changed_session_buy_ord_volume_value=this.m_struct_curr_symbol.session_buy_ord_volume-this.m_struct_prev_symbol.session_buy_ord_volume;
      if(this.m_changed_session_buy_ord_volume_value>this.m_control_session_buy_ord_volume_inc)
        {
         this.m_is_change_session_buy_ord_volume_inc=true;
         event_id=SYMBOL_EVENT_SESSION_BUY_ORD_VOLUME_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_buy_ord_volume_value,this.Name()))
            this.m_struct_prev_symbol.session_buy_ord_volume=this.m_struct_curr_symbol.session_buy_ord_volume;
        }
      else if(this.m_changed_session_buy_ord_volume_value<-this.m_control_session_buy_ord_volume_dec)
        {
         this.m_is_change_session_buy_ord_volume_dec=true;
         event_id=SYMBOL_EVENT_SESSION_BUY_ORD_VOLUME_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_buy_ord_volume_value,this.Name()))
            this.m_struct_prev_symbol.session_buy_ord_volume=this.m_struct_curr_symbol.session_buy_ord_volume;
        }
     }
//--- Change of the current total volume of sell orders
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_SELL_ORD_VOLUME))
     {
      this.m_changed_session_sell_ord_volume_value=this.m_struct_curr_symbol.session_sell_ord_volume-this.m_struct_prev_symbol.session_sell_ord_volume;
      if(this.m_changed_session_sell_ord_volume_value>this.m_control_session_sell_ord_volume_inc)
        {
         this.m_is_change_session_sell_ord_volume_inc=true;
         event_id=SYMBOL_EVENT_SESSION_SELL_ORD_VOLUME_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_sell_ord_volume_value,this.Name()))
            this.m_struct_prev_symbol.session_sell_ord_volume=this.m_struct_curr_symbol.session_sell_ord_volume;
        }
      else if(this.m_changed_session_sell_ord_volume_value<-this.m_control_session_sell_ord_volume_dec)
        {
         this.m_is_change_session_sell_ord_volume_dec=true;
         event_id=SYMBOL_EVENT_SESSION_SELL_ORD_VOLUME_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_sell_ord_volume_value,this.Name()))
            this.m_struct_prev_symbol.session_sell_ord_volume=this.m_struct_curr_symbol.session_sell_ord_volume;
        }
     }
//--- Session open price change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_OPEN))
     {
      this.m_changed_session_open_value=this.m_struct_curr_symbol.session_open-this.m_struct_prev_symbol.session_open;
      if(this.m_changed_session_open_value>this.m_control_session_open_inc)
        {
         this.m_is_change_session_open_inc=true;
         event_id=SYMBOL_EVENT_SESSION_OPEN_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_open_value,this.Name()))
            this.m_struct_prev_symbol.session_open=this.m_struct_curr_symbol.session_open;
        }
      else if(this.m_changed_session_open_value<-this.m_control_session_open_dec)
        {
         this.m_is_change_session_open_dec=true;
         event_id=SYMBOL_EVENT_SESSION_OPEN_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_open_value,this.Name()))
            this.m_struct_prev_symbol.session_open=this.m_struct_curr_symbol.session_open;
        }
     }
//--- Session close price change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_CLOSE))
     {
      this.m_changed_session_close_value=this.m_struct_curr_symbol.session_close-this.m_struct_prev_symbol.session_close;
      if(this.m_changed_session_close_value>this.m_control_session_close_inc)
        {
         this.m_is_change_session_close_inc=true;
         event_id=SYMBOL_EVENT_SESSION_CLOSE_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_close_value,this.Name()))
            this.m_struct_prev_symbol.session_close=this.m_struct_curr_symbol.session_close;
        }
      else if(this.m_changed_session_close_value<-this.m_control_session_close_dec)
        {
         this.m_is_change_session_close_dec=true;
         event_id=SYMBOL_EVENT_SESSION_CLOSE_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_close_value,this.Name()))
            this.m_struct_prev_symbol.session_close=this.m_struct_curr_symbol.session_close;
        }
     }
//--- Average weighted session price change
   if(this.IsPresentEventFlag(SYMBOL_EVENT_FLAG_SESSION_AW))
     {
      this.m_changed_session_aw_value=this.m_struct_curr_symbol.session_aw-this.m_struct_prev_symbol.session_aw;
      if(this.m_changed_session_aw_value>this.m_control_session_aw_inc)
        {
         this.m_is_change_session_aw_inc=true;
         event_id=SYMBOL_EVENT_SESSION_AW_INC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_aw_value,this.Name()))
            this.m_struct_prev_symbol.session_aw=this.m_struct_curr_symbol.session_aw;
        }
      else if(this.m_changed_session_aw_value<-this.m_control_session_aw_dec)
        {
         this.m_is_change_session_aw_dec=true;
         event_id=SYMBOL_EVENT_SESSION_AW_DEC;
         if(this.EventAdd(event_id,this.TickTime(),this.m_changed_session_aw_value,this.Name()))
            this.m_struct_prev_symbol.session_aw=this.m_struct_curr_symbol.session_aw;
        }
     }
  }
//+------------------------------------------------------------------+

O método é bastante "pesado", mas apenas devido a blocos de verificações idênticas para alterações nas propriedades rastreadas do símbolo. Na parte 13, já analisamos um método semelhante ao rastrear alterações na conta. Aqui a lógica é semelhante, exceto que agora temos toda a funcionalidade para armazenar eventos localizados no objeto base CBaseObj.
Consideremos como exemplo a alteração do preço médio ponderado da sessão.
No início do método, zeramos os valores das propriedades rastreadas usando o método InitChangesParams() e definimos o status do evento como "Nenhum evento".

  • Com a ajuda do método IsPresentEventFlag(), localizado também no objeto base, verificamos se o sinalizador de alteração de valor SYMBOL_SESSION_AW do símbolo existe no código de evento registrado na variável m_event_code.
    Se o sinalizador de alteração do valor estiver no código do evento,
    • calculamos o valor da alteração nesta propriedade e verificamos se o valor excede o valor controlado.
      • Se o valor calculado for maior do que o valor controlado,
        • definimos o sinalizador do evento de aumento do preço médio ponderado,
        • escrevemos no identificador de evento "Evento de aumento de preço médio ponderado" e
        • chamamos o método de adição de evento à lista EventAdd() da classe base CBaseObj.
          Se o evento foi adicionado com êxito à lista,
          • salvamos o valor atual da propriedade como o anterior para verificação adicional.
Para registrar o evento de diminuição no valor da propriedade, realizamos todas as verificações exatamente da mesma forma, apenas verificamos a diminuição no valor maior que o valor controlado.
No método de adição de evento à lista EventAdd(), enviamos os dados:
  1. identificador de evento (event_id preenchido ao verificar o evento)
  2. hora atual em milissegundos (método TickTime() da classe base CBaseObj)
  3. valor calculado da alteração na propriedade do símbolo (m_changed_session_aw_value)
  4. nome do objeto (neste caso, nome do símbolo)

Também faremos uma pequena alteração no construtor protegido da classe, uma vez qque para que o objeto-símbolo preencha a nova propriedade "índice de símbolo na janela Observação do Mercado", precisamos passar esse índice ao rastrear símbolos na Observação do Mercado. Nós vamos transmitir o índice diretamente para o construtor da classe:

protected:
//--- Protected parametric constructor
                     CSymbol(ENUM_SYMBOL_STATUS symbol_status,const string name,const int index);

No mesmo local, na seção protegida da classe, adicionamos outro método que retorna o número de casas decimais de acordo com o método de cálculo de swap:

//--- Get and return integer properties of a selected symbol from its parameters
   bool              SymbolExists(const string name)     const;
   long              SymbolExists(void)                  const;
   long              SymbolCustom(void)                  const;
   long              SymbolChartMode(void)               const;
   long              SymbolMarginHedgedUseLEG(void)      const;
   long              SymbolOrderFillingMode(void)        const;
   long              SymbolOrderMode(void)               const;
   long              SymbolExpirationMode(void)          const;
   long              SymbolOrderGTCMode(void)            const;
   long              SymbolOptionMode(void)              const;
   long              SymbolOptionRight(void)             const;
   long              SymbolBackgroundColor(void)         const;
   long              SymbolCalcMode(void)                const;
   long              SymbolSwapMode(void)                const;
   long              SymbolDigitsLot(void);
   int               SymbolDigitsBySwap(void);
//--- Get and return real properties of a selected symbol from its parameters

Acontece que os swaps são cobrados em dinheiro, em pontos e em porcentagem. Além disso, para cada um destes tipos de cálculo de swaps, é necessário retornar o valor correspondente do número de casas decimais. Este método os retorna. Vamos escrevê-lo fora do corpo da classe:

//+------------------------------------------------------------------+
//| Return the number of decimal places                              |
//| depending on the swap calculation method                         |
//+------------------------------------------------------------------+
int CSymbol::SymbolDigitsBySwap(void)
  {
   return
     (
      this.SwapMode()==SYMBOL_SWAP_MODE_POINTS           || 
      this.SwapMode()==SYMBOL_SWAP_MODE_REOPEN_CURRENT   || 
      this.SwapMode()==SYMBOL_SWAP_MODE_REOPEN_BID       ?  this.Digits() :
      this.SwapMode()==SYMBOL_SWAP_MODE_CURRENCY_SYMBOL  || 
      this.SwapMode()==SYMBOL_SWAP_MODE_CURRENCY_MARGIN  || 
      this.SwapMode()==SYMBOL_SWAP_MODE_CURRENCY_DEPOSIT ?  this.DigitsCurrency():
      this.SwapMode()==SYMBOL_SWAP_MODE_INTEREST_CURRENT || 
      this.SwapMode()==SYMBOL_SWAP_MODE_INTEREST_OPEN    ?  1  :  0
     );
  }  
//+------------------------------------------------------------------+

Fazemos com que o método Refresh() seja virtual, uma vez que é definido na classe base de objetos CBaseObj. Mudamos o tipo de método - para atualizar os dados de cotação RefreshRates() - de void para bool, uma vez que agora no início do método Refresh(), o método RefreshRates() será chamado. Além disso, se não for possível obter dados nele, o método retornará false, encerrando imediatamente o método Refresh().
Adicionamos a definição do método que retorna a descrição do evento do símbolo:

//--- Update all symbol data
   virtual void      Refresh(void);
//--- Update quote data by a symbol
   bool              RefreshRates(void);
//--- Return description of symbol events
   string            EventDescription(const ENUM_SYMBOL_EVENT event);

Na seção pública da classe, na seção de métodos de acesso simplificado, nos métodos que retornam as propriedades inteiras do símbolo,
adicionamos o método de retorno do índice do símbolo na janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Methods of a simplified access to the order object properties    |
//+------------------------------------------------------------------+
//--- Integer properties
   long              Status(void)                                 const { return this.GetProperty(SYMBOL_PROP_STATUS);                                      }
   int               IndexInMarketWatch(void)                     const { return (int)this.GetProperty(SYMBOL_PROP_INDEX_MW);                               }
   bool              IsCustom(void)                               const { return (bool)this.GetProperty(SYMBOL_PROP_CUSTOM);                                }
   color             ColorBackground(void)                        const { return (color)this.GetProperty(SYMBOL_PROP_BACKGROUND_COLOR);                     }
   ENUM_SYMBOL_CHART_MODE ChartMode(void)                         const { return (ENUM_SYMBOL_CHART_MODE)this.GetProperty(SYMBOL_PROP_CHART_MODE);          }
   bool              IsExist(void)                                const { return (bool)this.GetProperty(SYMBOL_PROP_EXIST);                                 }
   bool              IsExist(const string name)                   const { return this.SymbolExists(name);                                                   }
   bool              IsSelect(void)                               const { return (bool)this.GetProperty(SYMBOL_PROP_SELECT);                                }
   bool              IsVisible(void)                              const { return (bool)this.GetProperty(SYMBOL_PROP_VISIBLE);                               }
   long              SessionDeals(void)                           const { return this.GetProperty(SYMBOL_PROP_SESSION_DEALS);                               }
   long              SessionBuyOrders(void)                       const { return this.GetProperty(SYMBOL_PROP_SESSION_BUY_ORDERS);                          }
   long              SessionSellOrders(void)                      const { return this.GetProperty(SYMBOL_PROP_SESSION_SELL_ORDERS);                         }
   long              Volume(void)                                 const { return this.GetProperty(SYMBOL_PROP_VOLUME);                                      }
   long              VolumeHigh(void)                             const { return this.GetProperty(SYMBOL_PROP_VOLUMEHIGH);                                  }
   long              VolumeLow(void)                              const { return this.GetProperty(SYMBOL_PROP_VOLUMELOW);                                   }
   datetime          Time(void)                                   const { return (datetime)this.GetProperty(SYMBOL_PROP_TIME);                              }
   int               Digits(void)                                 const { return (int)this.GetProperty(SYMBOL_PROP_DIGITS);                                 }
   int               DigitsLot(void)                              const { return (int)this.GetProperty(SYMBOL_PROP_DIGITS_LOTS);                            }
   int               Spread(void)                                 const { return (int)this.GetProperty(SYMBOL_PROP_SPREAD);                                 }
   bool              IsSpreadFloat(void)                          const { return (bool)this.GetProperty(SYMBOL_PROP_SPREAD_FLOAT);                          }
   int               TicksBookdepth(void)                         const { return (int)this.GetProperty(SYMBOL_PROP_TICKS_BOOKDEPTH);                        }
   ENUM_SYMBOL_CALC_MODE TradeCalcMode(void)                      const { return (ENUM_SYMBOL_CALC_MODE)this.GetProperty(SYMBOL_PROP_TRADE_CALC_MODE);      }
   ENUM_SYMBOL_TRADE_MODE TradeMode(void)                         const { return (ENUM_SYMBOL_TRADE_MODE)this.GetProperty(SYMBOL_PROP_TRADE_MODE);          }
   datetime          StartTime(void)                              const { return (datetime)this.GetProperty(SYMBOL_PROP_START_TIME);                        }
   datetime          ExpirationTime(void)                         const { return (datetime)this.GetProperty(SYMBOL_PROP_EXPIRATION_TIME);                   }
   int               TradeStopLevel(void)                         const { return (int)this.GetProperty(SYMBOL_PROP_TRADE_STOPS_LEVEL);                      }
   int               TradeFreezeLevel(void)                       const { return (int)this.GetProperty(SYMBOL_PROP_TRADE_FREEZE_LEVEL);                     }
   ENUM_SYMBOL_TRADE_EXECUTION TradeExecutionMode(void)           const { return (ENUM_SYMBOL_TRADE_EXECUTION)this.GetProperty(SYMBOL_PROP_TRADE_EXEMODE);  }
   ENUM_SYMBOL_SWAP_MODE SwapMode(void)                           const { return (ENUM_SYMBOL_SWAP_MODE)this.GetProperty(SYMBOL_PROP_SWAP_MODE);            }
   ENUM_DAY_OF_WEEK  SwapRollover3Days(void)                      const { return (ENUM_DAY_OF_WEEK)this.GetProperty(SYMBOL_PROP_SWAP_ROLLOVER3DAYS);        }
   bool              IsMarginHedgedUseLeg(void)                   const { return (bool)this.GetProperty(SYMBOL_PROP_MARGIN_HEDGED_USE_LEG);                 }
   int               ExpirationModeFlags(void)                    const { return (int)this.GetProperty(SYMBOL_PROP_EXPIRATION_MODE);                        }
   int               FillingModeFlags(void)                       const { return (int)this.GetProperty(SYMBOL_PROP_FILLING_MODE);                           }
   int               OrderModeFlags(void)                         const { return (int)this.GetProperty(SYMBOL_PROP_ORDER_MODE);                             }
   ENUM_SYMBOL_ORDER_GTC_MODE OrderModeGTC(void)                  const { return (ENUM_SYMBOL_ORDER_GTC_MODE)this.GetProperty(SYMBOL_PROP_ORDER_GTC_MODE);  }
   ENUM_SYMBOL_OPTION_MODE OptionMode(void)                       const { return (ENUM_SYMBOL_OPTION_MODE)this.GetProperty(SYMBOL_PROP_OPTION_MODE);        }
   ENUM_SYMBOL_OPTION_RIGHT OptionRight(void)                     const { return (ENUM_SYMBOL_OPTION_RIGHT)this.GetProperty(SYMBOL_PROP_OPTION_RIGHT);      }
//--- Real properties

Nos métodos que retornam propriedades reais
adicionamos o método de retorno do preço Bid ou Last, o método de retorno do preço Bid ou Last máximo do dia e o método de retorno do preço Bid ou Last mínimo do dia:

//--- Real properties
   double            Bid(void)                                    const { return this.GetProperty(SYMBOL_PROP_BID);                                         }
   double            BidHigh(void)                                const { return this.GetProperty(SYMBOL_PROP_BIDHIGH);                                     }
   double            BidLow(void)                                 const { return this.GetProperty(SYMBOL_PROP_BIDLOW);                                      }
   double            Ask(void)                                    const { return this.GetProperty(SYMBOL_PROP_ASK);                                         }
   double            AskHigh(void)                                const { return this.GetProperty(SYMBOL_PROP_ASKHIGH);                                     }
   double            AskLow(void)                                 const { return this.GetProperty(SYMBOL_PROP_ASKLOW);                                      }
   double            Last(void)                                   const { return this.GetProperty(SYMBOL_PROP_LAST);                                        }
   double            LastHigh(void)                               const { return this.GetProperty(SYMBOL_PROP_LASTHIGH);                                    }
   double            LastLow(void)                                const { return this.GetProperty(SYMBOL_PROP_LASTLOW);                                     }
   double            VolumeReal(void)                             const { return this.GetProperty(SYMBOL_PROP_VOLUME_REAL);                                 }
   double            VolumeHighReal(void)                         const { return this.GetProperty(SYMBOL_PROP_VOLUMEHIGH_REAL);                             }
   double            VolumeLowReal(void)                          const { return this.GetProperty(SYMBOL_PROP_VOLUMELOW_REAL);                              }
   double            OptionStrike(void)                           const { return this.GetProperty(SYMBOL_PROP_OPTION_STRIKE);                               }
   double            Point(void)                                  const { return this.GetProperty(SYMBOL_PROP_POINT);                                       }
   double            TradeTickValue(void)                         const { return this.GetProperty(SYMBOL_PROP_TRADE_TICK_VALUE);                            }
   double            TradeTickValueProfit(void)                   const { return this.GetProperty(SYMBOL_PROP_TRADE_TICK_VALUE_PROFIT);                     }
   double            TradeTickValueLoss(void)                     const { return this.GetProperty(SYMBOL_PROP_TRADE_TICK_VALUE_LOSS);                       }
   double            TradeTickSize(void)                          const { return this.GetProperty(SYMBOL_PROP_TRADE_TICK_SIZE);                             }
   double            TradeContractSize(void)                      const { return this.GetProperty(SYMBOL_PROP_TRADE_CONTRACT_SIZE);                         }
   double            TradeAccuredInterest(void)                   const { return this.GetProperty(SYMBOL_PROP_TRADE_ACCRUED_INTEREST);                      }
   double            TradeFaceValue(void)                         const { return this.GetProperty(SYMBOL_PROP_TRADE_FACE_VALUE);                            }
   double            TradeLiquidityRate(void)                     const { return this.GetProperty(SYMBOL_PROP_TRADE_LIQUIDITY_RATE);                        }
   double            LotsMin(void)                                const { return this.GetProperty(SYMBOL_PROP_VOLUME_MIN);                                  }
   double            LotsMax(void)                                const { return this.GetProperty(SYMBOL_PROP_VOLUME_MAX);                                  }
   double            LotsStep(void)                               const { return this.GetProperty(SYMBOL_PROP_VOLUME_STEP);                                 }
   double            VolumeLimit(void)                            const { return this.GetProperty(SYMBOL_PROP_VOLUME_LIMIT);                                }
   double            SwapLong(void)                               const { return this.GetProperty(SYMBOL_PROP_SWAP_LONG);                                   }
   double            SwapShort(void)                              const { return this.GetProperty(SYMBOL_PROP_SWAP_SHORT);                                  }
   double            MarginInitial(void)                          const { return this.GetProperty(SYMBOL_PROP_MARGIN_INITIAL);                              }
   double            MarginMaintenance(void)                      const { return this.GetProperty(SYMBOL_PROP_MARGIN_MAINTENANCE);                          }
   double            MarginLongInitial(void)                      const { return this.GetProperty(SYMBOL_PROP_MARGIN_LONG_INITIAL);                         }
   double            MarginBuyStopInitial(void)                   const { return this.GetProperty(SYMBOL_PROP_MARGIN_BUY_STOP_INITIAL);                     }
   double            MarginBuyLimitInitial(void)                  const { return this.GetProperty(SYMBOL_PROP_MARGIN_BUY_LIMIT_INITIAL);                    }
   double            MarginBuyStopLimitInitial(void)              const { return this.GetProperty(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_INITIAL);                }
   double            MarginLongMaintenance(void)                  const { return this.GetProperty(SYMBOL_PROP_MARGIN_LONG_MAINTENANCE);                     }
   double            MarginBuyStopMaintenance(void)               const { return this.GetProperty(SYMBOL_PROP_MARGIN_BUY_STOP_MAINTENANCE);                 }
   double            MarginBuyLimitMaintenance(void)              const { return this.GetProperty(SYMBOL_PROP_MARGIN_BUY_LIMIT_MAINTENANCE);                }
   double            MarginBuyStopLimitMaintenance(void)          const { return this.GetProperty(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_MAINTENANCE);            }
   double            MarginShortInitial(void)                     const { return this.GetProperty(SYMBOL_PROP_MARGIN_SHORT_INITIAL);                        }
   double            MarginSellStopInitial(void)                  const { return this.GetProperty(SYMBOL_PROP_MARGIN_SELL_STOP_INITIAL);                    }
   double            MarginSellLimitInitial(void)                 const { return this.GetProperty(SYMBOL_PROP_MARGIN_SELL_LIMIT_INITIAL);                   }
   double            MarginSellStopLimitInitial(void)             const { return this.GetProperty(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_INITIAL);               }
   double            MarginShortMaintenance(void)                 const { return this.GetProperty(SYMBOL_PROP_MARGIN_SHORT_MAINTENANCE);                    }
   double            MarginSellStopMaintenance(void)              const { return this.GetProperty(SYMBOL_PROP_MARGIN_SELL_STOP_MAINTENANCE);                }
   double            MarginSellLimitMaintenance(void)             const { return this.GetProperty(SYMBOL_PROP_MARGIN_SELL_LIMIT_MAINTENANCE);               }
   double            MarginSellStopLimitMaintenance(void)         const { return this.GetProperty(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_MAINTENANCE);           }
   double            SessionVolume(void)                          const { return this.GetProperty(SYMBOL_PROP_SESSION_VOLUME);                              }
   double            SessionTurnover(void)                        const { return this.GetProperty(SYMBOL_PROP_SESSION_TURNOVER);                            }
   double            SessionInterest(void)                        const { return this.GetProperty(SYMBOL_PROP_SESSION_INTEREST);                            }
   double            SessionBuyOrdersVolume(void)                 const { return this.GetProperty(SYMBOL_PROP_SESSION_BUY_ORDERS_VOLUME);                   }
   double            SessionSellOrdersVolume(void)                const { return this.GetProperty(SYMBOL_PROP_SESSION_SELL_ORDERS_VOLUME);                  }
   double            SessionOpen(void)                            const { return this.GetProperty(SYMBOL_PROP_SESSION_OPEN);                                }
   double            SessionClose(void)                           const { return this.GetProperty(SYMBOL_PROP_SESSION_CLOSE);                               }
   double            SessionAW(void)                              const { return this.GetProperty(SYMBOL_PROP_SESSION_AW);                                  }
   double            SessionPriceSettlement(void)                 const { return this.GetProperty(SYMBOL_PROP_SESSION_PRICE_SETTLEMENT);                    }
   double            SessionPriceLimitMin(void)                   const { return this.GetProperty(SYMBOL_PROP_SESSION_PRICE_LIMIT_MIN);                     }
   double            SessionPriceLimitMax(void)                   const { return this.GetProperty(SYMBOL_PROP_SESSION_PRICE_LIMIT_MAX);                     }
   double            MarginHedged(void)                           const { return this.GetProperty(SYMBOL_PROP_MARGIN_HEDGED);                               }
   double            NormalizedPrice(const double price)          const;
   double            BidLast(void)                                const;
   double            BidLastHigh(void)                            const;
   double            BidLastLow(void                            const;
//--- String properties

Fora do corpo da classe, escrevemos sua implementação:

//+------------------------------------------------------------------+
//| Return Bid or Last price                                         |
//| depending on the chart construction method                       |
//+------------------------------------------------------------------+
double CSymbol::BidLast(void) const
  {
   return(this.ChartMode()==SYMBOL_CHART_MODE_BID ? this.GetProperty(SYMBOL_PROP_BID) : this.GetProperty(SYMBOL_PROP_LAST));
  }  
//+------------------------------------------------------------------+
//| Return maximum Bid or Last price for a day                       |
//| depending on the chart construction method                       |
//+------------------------------------------------------------------+
double CSymbol::BidLastHigh(void) const
  {
   return(this.ChartMode()==SYMBOL_CHART_MODE_BID ? this.GetProperty(SYMBOL_PROP_BIDHIGH) : this.GetProperty(SYMBOL_PROP_LASTHIGH));
  }  
//+------------------------------------------------------------------+
//| Return minimum Bid or Last price for a day                       |
//| depending on the chart construction method                       |
//+------------------------------------------------------------------+
double CSymbol::BidLastLow(void) const
  {
   return(this.ChartMode()==SYMBOL_CHART_MODE_BID ? this.GetProperty(SYMBOL_PROP_BIDLOW) : this.GetProperty(SYMBOL_PROP_LASTLOW));
  }
//+------------------------------------------------------------------+

Tudo é simples aqui, pois dependendo dos preços usados para construir o gráfico, é retornada a propriedade correspondente do símbolo (para preços Bid ou Last).

Também na seção pública escrevemos os métodos de configuração de propriedades controladas, os métodos de retorno de alteração de propriedade e os sinalizadores de eventos do símbolo:

//+------------------------------------------------------------------+
//| Get and set the parameters of tracked changes                    |
//+------------------------------------------------------------------+
   //--- Execution
   //--- Flag of changing the trading mode for a symbol
   bool              IsChangedTradeMode(void)                              const { return this.m_is_change_trade_mode;                       } 
   //--- Current session deals
   //--- setting the controlled value of (1) growth, (2) decrease in the number of deals during the current session
   //--- getting (3) the number of deals change value during the current session,
   //--- getting the flag of the number of deals change during the current session exceeding the (4) growth, (5) decrease value
   void              SetControlSessionDealsInc(const long value)                 { this.m_control_session_deals_inc=::fabs(value);           }
   void              SetControlSessionDealsDec(const long value)                 { this.m_control_session_deals_dec=::fabs(value);           }
   long              GetValueChangedSessionDeals(void)                     const { return this.m_changed_session_deals_value;                }
   bool              IsIncreaseSessionDeals(void)                          const { return this.m_is_change_session_deals_inc;                }
   bool              IsDecreaseSessionDeals(void)                          const { return this.m_is_change_session_deals_dec;                }
   //--- Buy orders of the current session
   //--- setting the controlled value of (1) growth, (2) decrease in the current number of Buy orders
   //--- getting (3) the current number of Buy orders change value,
   //--- getting the flag of the current Buy orders' number change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionBuyOrdInc(const long value)                { this.m_control_session_buy_ord_inc=::fabs(value);         }
   void              SetControlSessionBuyOrdDec(const long value)                { this.m_control_session_buy_ord_dec=::fabs(value);         }
   long              GetValueChangedSessionBuyOrders(void)                 const { return this.m_changed_session_buy_ord_value;              }
   bool              IsIncreaseSessionBuyOrders(void)                      const { return this.m_is_change_session_buy_ord_inc;              }
   bool              IsDecreaseSessionBuyOrders(void)                      const { return this.m_is_change_session_buy_ord_dec;              }
   //--- Sell orders of the current session
   //--- setting the controlled value of (1) growth, (2) decrease in the current number of Sell orders
   //--- getting (3) the current number of Sell orders change value,
   //--- getting the flag of the current Sell orders' number change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionSellOrdInc(const long value)               { this.m_control_session_sell_ord_inc=::fabs(value);        }
   void              SetControlSessionSellOrdDec(const long value)               { this.m_control_session_sell_ord_dec=::fabs(value);        }
   long              GetValueChangedSessionSellOrders(void)                const { return this.m_changed_session_sell_ord_value;             }
   bool              IsIncreaseSessionSellOrders(void)                     const { return this.m_is_change_session_sell_ord_inc;             }
   bool              IsDecreaseSessionSellOrders(void)                     const { return this.m_is_change_session_sell_ord_dec;             }
   //--- Volume of the last deal
   //--- setting the last deal volume controlled (1) growth, (2) decrease value
   //--- getting (3) volume change values in the last deal,
   //--- getting the flag of the volume change in the last deal exceeding the (4) growth, (5) decrease value
   void              SetControlVolumeInc(const long value)                       { this.m_control_volume_inc=::fabs(value);                  }
   void              SetControlVolumeDec(const long value)                       { this.m_control_volume_dec=::fabs(value);                  }
   long              GetValueChangedVolume(void)                           const { return this.m_changed_volume_value;                       }
   bool              IsIncreaseVolume(void)                                const { return this.m_is_change_volume_inc;                       }
   bool              IsDecreaseVolume(void)                                const { return this.m_is_change_volume_dec;                       }
   //--- Maximum volume within a day
   //--- setting the maximum day volume controlled (1) growth, (2) decrease value
   //--- getting (3) the maximum volume change value within a day,
   //--- getting the flag of the maximum day volume change exceeding the (4) growth, (5) decrease value
   void              SetControlVolumeHighInc(const long value)                   { this.m_control_volume_high_day_inc=::fabs(value);         }
   void              SetControlVolumeHighDec(const long value)                   { this.m_control_volume_high_day_dec=::fabs(value);         }
   long              GetValueChangedVolumeHigh(void)                       const { return this.m_changed_volume_high_day_value;              }
   bool              IsIncreaseVolumeHigh(void)                            const { return this.m_is_change_volume_high_day_inc;              }
   bool              IsDecreaseVolumeHigh(void)                            const { return this.m_is_change_volume_high_day_dec;              }
   //--- Minimum volume within a day
   //--- setting the minimum day volume controlled (1) growth, (2) decrease value
   //--- getting (3) the minimum volume change value within a day,
   //--- getting the flag of the minimum day volume change exceeding the (4) growth, (5) decrease value
   void              SetControlVolumeLowInc(const long value)                    { this.m_control_volume_low_day_inc=::fabs(value);          }
   void              SetControlVolumeLowDec(const long value)                    { this.m_control_volume_low_day_dec=::fabs(value);          }
   long              GetValueChangedVolumeLow(void)                        const { return this.m_changed_volume_low_day_value;               }
   bool              IsIncreaseVolumeLow(void)                             const { return this.m_is_change_volume_low_day_inc;               }
   bool              IsDecreaseVolumeLow(void)                             const { return this.m_is_change_volume_low_day_dec;               }
   //--- Spread
   //--- setting the controlled spread decrease (1) growth, (2) decrease value in points
   //--- getting (3) spread change value in points,
   //--- getting the flag of the spread change in points exceeding the (4) growth, (5) decrease value
   void              SetControlSpreadInc(const int value)                        { this.m_control_spread_inc=::fabs(value);                  }
   void              SetControlSpreadDec(const int value)                        { this.m_control_spread_dec=::fabs(value);                  }
   int               GetValueChangedSpread(void)                           const { return this.m_changed_spread_value;                       }
   bool              IsIncreaseSpread(void)                                const { return this.m_is_change_spread_inc;                       }
   bool              IsDecreaseSpread(void)                                const { return this.m_is_change_spread_dec;                       }
   //--- StopLevel
   //--- setting the controlled StopLevel decrease (1) growth, (2) decrease value in points
   //--- getting (3) StopLevel change value in points,
   //--- getting the flag of StopLevel change in points exceeding the (4) growth, (5) decrease value
   void              SetControlStopLevelInc(const int value)                     { this.m_control_stops_level_inc=::fabs(value);             }
   void              SetControlStopLevelDec(const int value)                     { this.m_control_stops_level_dec=::fabs(value);             }
   int               GetValueChangedStopLevel(void)                        const { return this.m_changed_stops_level_value;                  }
   bool              IsIncreaseStopLevel(void)                             const { return this.m_is_change_stops_level_inc;                  }
   bool              IsDecreaseStopLevel(void)                             const { return this.m_is_change_stops_level_dec;                  }
   //--- Freeze distance
   //--- setting the controlled FreezeLevel decrease (1) growth, (2) decrease value in points
   //--- getting (3) FreezeLevel change value in points,
   //--- getting the flag of FreezeLevel change in points exceeding the (4) growth, (5) decrease value
   void              SetControlFreezeLevelInc(const int value)                   { this.m_control_freeze_level_inc=::fabs(value);            }
   void              SetControlFreezeLevelDec(const int value)                   { this.m_control_freeze_level_dec=::fabs(value);            }
   int               GetValueChangedFreezeLevel(void)                      const { return this.m_changed_freeze_level_value;                 }
   bool              IsIncreaseFreezeLevel(void)                           const { return this.m_is_change_freeze_level_inc;                 }
   bool              IsDecreaseFreezeLevel(void)                           const { return this.m_is_change_freeze_level_dec;                 }
   
   //--- Bid/Last
   //--- setting the Bid or Last price controlled (1) growth, (2) decrease value
   //--- getting (3) Bid or Last price change value,
   //--- getting the flag of the Bid or Last price change exceeding the (4) growth, (5) decrease value
   void              SetControlBidLastInc(const double value)                    { this.m_control_bid_last_inc=::fabs(value);                }
   void              SetControlBidLastDec(const double value)                    { this.m_control_bid_last_dec=::fabs(value);                }
   double            GetValueChangedBidLast(void)                          const { return this.m_changed_bid_last_value;                     }
   bool              IsIncreaseBidLast(void)                               const { return this.m_is_change_bid_last_inc;                     }
   bool              IsDecreaseBidLast(void)                               const { return this.m_is_change_bid_last_dec;                     }
   //--- Maximum Bid/Last of the day
   //--- setting the maximum Bid or Last price controlled (1) growth, (2) decrease value
   //--- getting the (3) maximum Bid or Last price change value,
   //--- getting the flag of the maximum Bid or Last price change exceeding the (4) growth, (5) decrease value
   void              SetControlBidLastHighInc(const double value)                { this.m_control_bid_last_high_inc=::fabs(value);           }
   void              SetControlBidLastHighDec(const double value)                { this.m_control_bid_last_high_dec=::fabs(value);           }
   double            GetValueChangedBidLastHigh(void)                      const { return this.m_changed_bid_last_high_value;                }
   bool              IsIncreaseBidLastHigh(void)                           const { return this.m_is_change_bid_last_high_inc;                }
   bool              IsDecreaseBidLastHigh(void)                           const { return this.m_is_change_bid_last_high_dec;                }
   //--- Minimum Bid/Last of the day
   //--- setting the minimum Bid or Last price controlled (1) growth, (2) decrease value
   //--- getting the (3) minimum Bid or Last price change value,
   //--- getting the flag of the minimum Bid or Last price change exceeding the (4) growth, (5) decrease value
   void              SetControlBidLastLowInc(const double value)                 { this.m_control_bid_last_low_inc=::fabs(value);            }
   void              SetControlBidLastLowDec(const double value)                 { this.m_control_bid_last_low_dec=::fabs(value);            }
   double            GetValueChangedBidLastLow(void)                       const { return this.m_changed_bid_last_low_value;                 }
   bool              IsIncreaseBidLastLow(void)                            const { return this.m_is_change_bid_last_low_inc;                 }
   bool              IsDecreaseBidLastLow(void)                            const { return this.m_is_change_bid_last_low_dec;                 }
   //--- Ask
   //--- setting the Ask price controlled (1) growth, (2) decrease value
   //--- getting (3) Ask price change value,
   //--- getting the flag of the Ask price change exceeding the (4) growth, (5) decrease value
   void              SetControlAskInc(const double value)                        { this.m_control_ask_inc=::fabs(value);                     }
   void              SetControlAskDec(const double value)                        { this.m_control_ask_dec=::fabs(value);                     }
   double            GetValueChangedAsk(void)                              const { return this.m_changed_ask_value;                          }
   bool              IsIncreaseAsk(void)                                   const { return this.m_is_change_ask_inc;                          }
   bool              IsDecreaseAsk(void)                                   const { return this.m_is_change_ask_dec;                          }
   //--- Maximum Ask price for the day
   //--- setting the maximum day Ask controlled (1) growth, (2) decrease value
   //--- getting (3) the maximum Ask change value within a day,
   //--- getting the flag of the maximum day Ask change exceeding the (4) growth, (5) decrease value
   void              SetControlAskHighInc(const double value)                    { this.m_control_ask_high_inc=::fabs(value);                }
   void              SetControlAskHighDec(const double value)                    { this.m_control_ask_high_dec=::fabs(value);                }
   double            GetValueChangedAskHigh(void)                          const { return this.m_changed_ask_high_value;                     }
   bool              IsIncreaseAskHigh(void)                               const { return this.m_is_change_ask_high_inc;                     }
   bool              IsDecreaseAskHigh(void)                               const { return this.m_is_change_ask_high_dec;                     }
   //--- Minimum Ask price for the day
   //--- setting the minimum day Ask controlled (1) growth, (2) decrease value
   //--- getting (3) the minimum Ask change value within a day,
   //--- getting the flag of the minimum day Ask change exceeding the (4) growth, (5) decrease value
   void              SetControlAskLowInc(const double value)                     { this.m_control_ask_low_inc=::fabs(value);                 }
   void              SetControlAskLowDec(const double value)                     { this.m_control_ask_low_dec=::fabs(value);                 }
   double            GetValueChangedAskLow(void)                           const { return this.m_changed_ask_low_value;                      }
   bool              IsIncreaseAskLow(void)                                const { return this.m_is_change_ask_low_inc;                      }
   bool              IsDecreaseAskLow(void)                                const { return this.m_is_change_ask_low_dec;                      }
   //--- Real Volume for the day
   //--- setting the real day volume controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the real day volume,
   //--- getting the flag of the real day volume change exceeding the (4) growth, (5) decrease value
   void              SetControlVolumeRealInc(const double value)                 { this.m_control_volume_real_inc=::fabs(value);             }
   void              SetControlVolumeRealDec(const double value)                 { this.m_control_volume_real_dec=::fabs(value);             }
   double            GetValueChangedVolumeReal(void)                       const { return this.m_changed_volume_real_value;                  }
   bool              IsIncreaseVolumeReal(void)                            const { return this.m_is_change_volume_real_inc;                  }
   bool              IsDecreaseVolumeReal(void)                            const { return this.m_is_change_volume_real_dec;                  }
   //--- Maximum real volume for the day
   //--- setting the maximum real day volume controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the maximum real day volume,
   //--- getting the flag of the maximum real day volume change exceeding the (4) growth, (5) decrease value
   void              SetControlVolumeHighRealInc(const double value)             { this.m_control_volume_high_real_day_inc=::fabs(value);    }
   void              SetControlVolumeHighRealDec(const double value)             { this.m_control_volume_high_real_day_dec=::fabs(value);    }
   double            GetValueChangedVolumeHighReal(void)                   const { return this.m_changed_volume_high_real_day_value;         }
   bool              IsIncreaseVolumeHighReal(void)                        const { return this.m_is_change_volume_high_real_day_inc;         }
   bool              IsDecreaseVolumeHighReal(void)                        const { return this.m_is_change_volume_high_real_day_dec;         }
   //--- Minimum real volume for the day
   //--- setting the minimum real day volume controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the minimum real day volume,
   //--- getting the flag of the minimum real day volume change exceeding the (4) growth, (5) decrease value
   void              SetControlVolumeLowRealInc(const double value)              { this.m_control_volume_low_real_day_inc=::fabs(value);     }
   void              SetControlVolumeLowRealDec(const double value)              { this.m_control_volume_low_real_day_dec=::fabs(value);     }
   double            GetValueChangedVolumeLowReal(void)                    const { return this.m_changed_volume_low_real_day_value;          }
   bool              IsIncreaseVolumeLowReal(void)                         const { return this.m_is_change_volume_low_real_day_inc;          }
   bool              IsDecreaseVolumeLowReal(void)                         const { return this.m_is_change_volume_low_real_day_dec;          }
   //--- Strike price
   //--- setting the strike price controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the strike price,
   //--- getting the flag of the strike price change exceeding the (4) growth, (5) decrease value
   void              SetControlOptionStrikeInc(const double value)               { this.m_control_option_strike_inc=::fabs(value);           }
   void              SetControlOptionStrikeDec(const double value)               { this.m_control_option_strike_dec=::fabs(value);           }
   double            GetValueChangedOptionStrike(void)                     const { return this.m_changed_option_strike_value;                } 
   bool              IsIncreaseOptionStrike(void)                          const { return this.m_is_change_option_strike_inc;                }
   bool              IsDecreaseOptionStrike(void)                          const { return this.m_is_change_option_strike_dec;                }
   //--- Maximum allowed total volume of unidirectional positions and orders
   //--- (1) getting the change value of the maximum allowed total volume of unidirectional positions and orders,
   //--- getting the flag of (2) increasing, (3) decreasing the maximum allowed total volume of unidirectional positions and orders
   double            GetValueChangedVolumeLimit(void)                      const { return this.m_changed_volume_limit_value;                 }
   bool              IsIncreaseVolumeLimit(void)                           const { return this.m_is_change_volume_limit_inc;                 }
   bool              IsDecreaseVolumeLimit(void)                           const { return this.m_is_change_volume_limit_dec;                 }
   //---  Swap long
   //--- (1) getting the swap long change value,
   //--- getting the flag of (2) increasing, (3) decreasing the swap long
   double            GetValueChangedSwapLong(void)                         const { return this.m_changed_swap_long_value;                    }
   bool              IsIncreaseSwapLong(void)                              const { return this.m_is_change_swap_long_inc;                    }
   bool              IsDecreaseSwapLong(void)                              const { return this.m_is_change_swap_long_dec;                    }
   //---  Swap short
   //--- (1) getting the swap short change value,
   //--- getting the flag of (2) increasing, (3) decreasing the swap short
   double            GetValueChangedSwapShort(void)                        const { return this.m_changed_swap_short_value;                   }
   bool              IsIncreaseSwapShort(void)                             const { return this.m_is_change_swap_short_inc;                   }
   bool              IsDecreaseSwapShort(void)                             const { return this.m_is_change_swap_short_dec;                   }
   //--- The total volume of deals in the current session
   //--- setting the controlled value of (1) growth, (2) decrease in the total volume of deals during the current session
   //--- getting (3) the total deal volume change value in the current session,
   //--- getting the flag of the total deal volume change during the current session exceeding the (4) growth, (5) decrease value
   void              SetControlSessionVolumeInc(const double value)              { this.m_control_session_volume_inc=::fabs(value);          }
   void              SetControlSessionVolumeDec(const double value)              { this.m_control_session_volume_dec=::fabs(value);          }
   double            GetValueChangedSessionVolume(void)                    const { return this.m_changed_session_volume_value;               }
   bool              IsIncreaseSessionVolume(void)                         const { return this.m_is_change_session_volume_inc;               }
   bool              IsDecreaseSessionVolume(void)                         const { return this.m_is_change_session_volume_dec;               }
   //--- The total turnover in the current session
   //--- setting the controlled value of the turnover (1) growth, (2) decrease during the current session
   //--- getting (3) the total turnover change value in the current session,
   //--- getting the flag of the total turnover change during the current session exceeding the (4) growth, (5) decrease value
   void              SetControlSessionTurnoverInc(const double value)            { this.m_control_session_turnover_inc=::fabs(value);        }
   void              SetControlSessionTurnoverDec(const double value)            { this.m_control_session_turnover_dec=::fabs(value);        }
   double            GetValueChangedSessionTurnover(void)                  const { return this.m_changed_session_turnover_value;             }
   bool              IsIncreaseSessionTurnover(void)                       const { return this.m_is_change_session_turnover_inc;             }
   bool              IsDecreaseSessionTurnover(void)                       const { return this.m_is_change_session_turnover_dec;             }
   //--- The total volume of open positions
   //--- setting the controlled value of (1) growth, (2) decrease in the total volume of open positions during the current session
   //--- getting (3) the change value of the open positions total volume in the current session,
   //--- getting the flag of the open positions total volume change during the current session exceeding the (4) growth, (5) decrease value
   void              SetControlSessionInterestInc(const double value)            { this.m_control_session_interest_inc=::fabs(value);        }
   void              SetControlSessionInterestDec(const double value)            { this.m_control_session_interest_dec=::fabs(value);        }
   double            GetValueChangedSessionInterest(void)                  const { return this.m_changed_session_interest_value;             }
   bool              IsIncreaseSessionInterest(void)                       const { return this.m_is_change_session_interest_inc;             }
   bool              IsDecreaseSessionInterest(void)                       const { return this.m_is_change_session_interest_dec;             }
   //--- The total volume of Buy orders at the moment
   //--- setting the controlled value of (1) growth, (2) decrease in the current total buy order volume
   //--- getting (3) the change value of the current total buy order volume,
   //--- getting the flag of the current total buy orders' volume change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionBuyOrdVolumeInc(const double value)        { this.m_control_session_buy_ord_volume_inc=::fabs(value);  }
   void              SetControlSessionBuyOrdVolumeDec(const double value)        { this.m_control_session_buy_ord_volume_dec=::fabs(value);  }
   double            GetValueChangedSessionBuyOrdVolume(void)              const { return this.m_changed_session_buy_ord_volume_value;       }
   bool              IsIncreaseSessionBuyOrdVolume(void)                   const { return this.m_is_change_session_buy_ord_volume_inc;       }
   bool              IsDecreaseSessionBuyOrdVolume(void)                   const { return this.m_is_change_session_buy_ord_volume_dec;       }
   //--- The total volume of Sell orders at the moment
   //--- setting the controlled value of (1) growth, (2) decrease in the current total sell order volume
   //--- getting (3) the change value of the current total sell order volume,
   //--- getting the flag of the current total sell orders' volume change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionSellOrdVolumeInc(const double value)       { this.m_control_session_sell_ord_volume_inc=::fabs(value); }
   void              SetControlSessionSellOrdVolumeDec(const double value)       { this.m_control_session_sell_ord_volume_dec=::fabs(value); }
   double            GetValueChangedSessionSellOrdVolume(void)             const { return this.m_changed_session_sell_ord_volume_value;      }
   bool              IsIncreaseSessionSellOrdVolume(void)                  const { return this.m_is_change_session_sell_ord_volume_inc;      }
   bool              IsDecreaseSessionSellOrdVolume(void)                  const { return this.m_is_change_session_sell_ord_volume_dec;      }
   //--- Session open price
   //--- setting the session open price controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the session open price,
   //--- getting the flag of the session open price change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionPriceOpenInc(const double value)           { this.m_control_session_open_inc=::fabs(value);            }
   void              SetControlSessionPriceOpenDec(const double value)           { this.m_control_session_open_dec=::fabs(value);            }
   double            GetValueChangedSessionPriceOpen(void)                 const { return this.m_changed_session_open_value;                 }
   bool              IsIncreaseSessionPriceOpen(void)                      const { return this.m_is_change_session_open_inc;                 }
   bool              IsDecreaseSessionPriceOpen(void)                      const { return this.m_is_change_session_open_dec;                 }
   //--- Session close price
   //--- setting the session close price controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the session close price,
   //--- getting the flag of the session close price change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionPriceCloseInc(const double value)          { this.m_control_session_close_inc=::fabs(value);           }
   void              SetControlSessionPriceCloseDec(const double value)          { this.m_control_session_close_dec=::fabs(value);           }
   double            GetValueChangedSessionPriceClose(void)                const { return this.m_changed_session_close_value;                }
   bool              IsIncreaseSessionPriceClose(void)                     const { return this.m_is_change_session_close_inc;                }
   bool              IsDecreaseSessionPriceClose(void)                     const { return this.m_is_change_session_close_dec;                }
   //--- The average weighted session price
   //--- setting the average weighted session price controlled (1) growth, (2) decrease value
   //--- getting (3) the change value of the average weighted session price,
   //--- getting the flag of the average weighted session price change exceeding the (4) growth, (5) decrease value
   void              SetControlSessionPriceAWInc(const double value)             { this.m_control_session_aw_inc=::fabs(value);              }
   void              SetControlSessionPriceAWDec(const double value)             { this.m_control_session_aw_dec=::fabs(value);              }
   double            GetValueChangedSessionPriceAW(void)                   const { return this.m_changed_session_aw_value;                   }
   bool              IsIncreaseSessionPriceAW(void)                        const { return this.m_is_change_session_aw_inc;                   }
   bool              IsDecreaseSessionPriceAW(void)                        const { return this.m_is_change_session_aw_dec;                   }
//---


Aqui, para cada uma das propriedades controladas, existem métodos para definir o valor controlado da alteração da propriedade, que quando excedido gera um evento cujo sinalizador pode ser obtido usando o método que retorna o sinalizador do evento e o valor da alteração (com a ajuda do método que retorna esse valor). Analisamos métodos semelhantes ao criar o acompanhamento de eventos da conta na parte 13 da descrição da biblioteca.

O construtor da classe possui algumas alterações:

//+------------------------------------------------------------------+
//| Closed parametric constructor                                    |
//+------------------------------------------------------------------+
CSymbol::CSymbol(ENUM_SYMBOL_STATUS symbol_status,const string name,const int index)
  {
   this.m_name=name;
   if(!this.Exist())
     {
      ::Print(DFUN_ERR_LINE,"\"",this.m_name,"\"",": ",TextByLanguage("Ошибка. Такого символа нет на сервере","Error. There is no such symbol on the server"));
      this.m_global_error=ERR_MARKET_UNKNOWN_SYMBOL;
     }
   bool select=::SymbolInfoInteger(this.m_name,SYMBOL_SELECT);
   ::ResetLastError();
   if(!select)
     {
      if(!this.SetToMarketWatch())
        {
         this.m_global_error=::GetLastError();
         ::Print(DFUN_ERR_LINE,"\"",this.m_name,"\": ",TextByLanguage("Не удалось поместить в обзор рынка. Ошибка: ","Failed to put in the market watch. Error: "),this.m_global_error);
        }
     }
   ::ResetLastError();
   if(!::SymbolInfoTick(this.m_name,this.m_tick))
     {
      this.m_global_error=::GetLastError();
      ::Print(DFUN_ERR_LINE,"\"",this.m_name,"\": ",TextByLanguage("Не удалось получить текущие цены. Ошибка: ","Could not get current prices. Error: "),this.m_global_error);
     }
//--- Initialize data
   this.Reset();
   this.InitMarginRates();
   ::ZeroMemory(this.m_struct_prev_symbol);
   this.m_struct_prev_symbol.trade_mode=WRONG_VALUE;
   this.InitChangesParams();
   this.InitControlsParams();
#ifdef __MQL5__
   ::ResetLastError();
   if(!this.MarginRates())
     {
      this.m_global_error=::GetLastError();
      ::Print(DFUN_ERR_LINE,this.Name(),": ",TextByLanguage("Не удалось получить коэффициенты взимания маржи. Ошибка: ","Failed to get margin rates. Error: "),this.m_global_error);
      return;
     }
#endif 
   
//--- Save integer properties
   this.m_long_prop[SYMBOL_PROP_STATUS]                                             = symbol_status;
   this.m_long_prop[SYMBOL_PROP_INDEX_MW]                                           = index;
   this.m_long_prop[SYMBOL_PROP_VOLUME]                                             = (long)this.m_tick.volume;
   this.m_long_prop[SYMBOL_PROP_SELECT]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SELECT);
   this.m_long_prop[SYMBOL_PROP_VISIBLE]                                            = ::SymbolInfoInteger(this.m_name,SYMBOL_VISIBLE);
   this.m_long_prop[SYMBOL_PROP_SESSION_DEALS]                                      = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_DEALS);
   this.m_long_prop[SYMBOL_PROP_SESSION_BUY_ORDERS]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_BUY_ORDERS);
   this.m_long_prop[SYMBOL_PROP_SESSION_SELL_ORDERS]                                = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_SELL_ORDERS);
   this.m_long_prop[SYMBOL_PROP_VOLUMEHIGH]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMEHIGH);
   this.m_long_prop[SYMBOL_PROP_VOLUMELOW]                                          = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMELOW);
   this.m_long_prop[SYMBOL_PROP_DIGITS]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_DIGITS);
   this.m_long_prop[SYMBOL_PROP_SPREAD]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SPREAD);
   this.m_long_prop[SYMBOL_PROP_SPREAD_FLOAT]                                       = ::SymbolInfoInteger(this.m_name,SYMBOL_SPREAD_FLOAT);
   this.m_long_prop[SYMBOL_PROP_TICKS_BOOKDEPTH]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_TICKS_BOOKDEPTH);
   this.m_long_prop[SYMBOL_PROP_TRADE_MODE]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_MODE);
   this.m_long_prop[SYMBOL_PROP_START_TIME]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_START_TIME);
   this.m_long_prop[SYMBOL_PROP_EXPIRATION_TIME]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_EXPIRATION_TIME);
   this.m_long_prop[SYMBOL_PROP_TRADE_STOPS_LEVEL]                                  = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_STOPS_LEVEL);
   this.m_long_prop[SYMBOL_PROP_TRADE_FREEZE_LEVEL]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_FREEZE_LEVEL);
   this.m_long_prop[SYMBOL_PROP_TRADE_EXEMODE]                                      = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_EXEMODE);
   this.m_long_prop[SYMBOL_PROP_SWAP_ROLLOVER3DAYS]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_SWAP_ROLLOVER3DAYS);
   this.m_long_prop[SYMBOL_PROP_TIME]                                               = this.TickTime();
   this.m_long_prop[SYMBOL_PROP_EXIST]                                              = this.SymbolExists();
   this.m_long_prop[SYMBOL_PROP_CUSTOM]                                             = this.SymbolCustom();
   this.m_long_prop[SYMBOL_PROP_MARGIN_HEDGED_USE_LEG]                              = this.SymbolMarginHedgedUseLEG();
   this.m_long_prop[SYMBOL_PROP_ORDER_MODE]                                         = this.SymbolOrderMode();
   this.m_long_prop[SYMBOL_PROP_FILLING_MODE]                                       = this.SymbolOrderFillingMode();
   this.m_long_prop[SYMBOL_PROP_EXPIRATION_MODE]                                    = this.SymbolExpirationMode();
   this.m_long_prop[SYMBOL_PROP_ORDER_GTC_MODE]                                     = this.SymbolOrderGTCMode();
   this.m_long_prop[SYMBOL_PROP_OPTION_MODE]                                        = this.SymbolOptionMode();
   this.m_long_prop[SYMBOL_PROP_OPTION_RIGHT]                                       = this.SymbolOptionRight();
   this.m_long_prop[SYMBOL_PROP_BACKGROUND_COLOR]                                   = this.SymbolBackgroundColor();
   this.m_long_prop[SYMBOL_PROP_CHART_MODE]                                         = this.SymbolChartMode();
   this.m_long_prop[SYMBOL_PROP_TRADE_CALC_MODE]                                    = this.SymbolCalcMode();
   this.m_long_prop[SYMBOL_PROP_SWAP_MODE]                                          = this.SymbolSwapMode();
//--- Save real properties
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASKHIGH)]                          = ::SymbolInfoDouble(this.m_name,SYMBOL_ASKHIGH);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASKLOW)]                           = ::SymbolInfoDouble(this.m_name,SYMBOL_ASKLOW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LASTHIGH)]                         = ::SymbolInfoDouble(this.m_name,SYMBOL_LASTHIGH);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LASTLOW)]                          = ::SymbolInfoDouble(this.m_name,SYMBOL_LASTLOW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_POINT)]                            = ::SymbolInfoDouble(this.m_name,SYMBOL_POINT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_PROFIT)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_PROFIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_LOSS)]            = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_LOSS);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_SIZE)]                  = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_CONTRACT_SIZE)]              = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_CONTRACT_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MIN)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MAX)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_STEP)]                      = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_STEP);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_LIMIT)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_LIMIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_LONG)]                        = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_LONG);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_SHORT)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_SHORT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_INITIAL)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_INITIAL);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_MAINTENANCE)]               = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_MAINTENANCE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_VOLUME)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_TURNOVER)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_TURNOVER);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_INTEREST)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_INTEREST);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_BUY_ORDERS_VOLUME)]        = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_BUY_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_SELL_ORDERS_VOLUME)]       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_SELL_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_OPEN)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_OPEN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_CLOSE)]                    = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_CLOSE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_AW)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_AW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_SETTLEMENT)]         = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_SETTLEMENT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MIN)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MAX)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BID)]                              = this.m_tick.bid;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASK)]                              = this.m_tick.ask;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LAST)]                             = this.m_tick.last;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BIDHIGH)]                          = this.SymbolBidHigh();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BIDLOW)]                           = this.SymbolBidLow();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_REAL)]                      = this.SymbolVolumeReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMEHIGH_REAL)]                  = this.SymbolVolumeHighReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMELOW_REAL)]                   = this.SymbolVolumeLowReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_OPTION_STRIKE)]                    = this.SymbolOptionStrike();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_ACCRUED_INTEREST)]           = this.SymbolTradeAccruedInterest();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_FACE_VALUE)]                 = this.SymbolTradeFaceValue();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_LIQUIDITY_RATE)]             = this.SymbolTradeLiquidityRate();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_HEDGED)]                    = this.SymbolMarginHedged();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_INITIAL)]              = this.m_margin_rate.Long.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_INITIAL)]          = this.m_margin_rate.BuyStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_INITIAL)]         = this.m_margin_rate.BuyLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_INITIAL)]     = this.m_margin_rate.BuyStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_MAINTENANCE)]          = this.m_margin_rate.Long.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_MAINTENANCE)]      = this.m_margin_rate.BuyStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_MAINTENANCE)]     = this.m_margin_rate.BuyLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_MAINTENANCE)] = this.m_margin_rate.BuyStopLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_INITIAL)]             = this.m_margin_rate.Short.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_INITIAL)]         = this.m_margin_rate.SellStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_INITIAL)]        = this.m_margin_rate.SellLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_INITIAL)]    = this.m_margin_rate.SellStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_MAINTENANCE)]         = this.m_margin_rate.Short.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_MAINTENANCE)]     = this.m_margin_rate.SellStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_MAINTENANCE)]    = this.m_margin_rate.SellLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_MAINTENANCE)]= this.m_margin_rate.SellStopLimit.Maintenance;
//--- Save string properties
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_NAME)]                             = this.m_name;
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CURRENCY_BASE)]                    = ::SymbolInfoString(this.m_name,SYMBOL_CURRENCY_BASE);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CURRENCY_PROFIT)]                  = ::SymbolInfoString(this.m_name,SYMBOL_CURRENCY_PROFIT);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CURRENCY_MARGIN)]                  = ::SymbolInfoString(this.m_name,SYMBOL_CURRENCY_MARGIN);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_DESCRIPTION)]                      = ::SymbolInfoString(this.m_name,SYMBOL_DESCRIPTION);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_PATH)]                             = ::SymbolInfoString(this.m_name,SYMBOL_PATH);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_BASIS)]                            = this.SymbolBasis();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_BANK)]                             = this.SymbolBank();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_ISIN)]                             = this.SymbolISIN();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_FORMULA)]                          = this.SymbolFormula();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_PAGE)]                             = this.SymbolPage();
//--- Save additional integer properties
   this.m_long_prop[SYMBOL_PROP_DIGITS_LOTS]                                        = this.SymbolDigitsLot();
//---
   if(!select)
      this.RemoveFromMarketWatch();
  }
//+------------------------------------------------------------------+

Agora, para o construtor é transferido o índice do símbolo na janela "Observação do Mercado", o nome do símbolo é atribuído ao nome do objetoé redefinida a estrutura de dados anteriores do símbolo, no campo da estrutura de eventos anteriores trade_mode é registrado o valor WRONG_VALUE — segundo com a presença deste valor no campo de modo de negociação do símbolo, vamos determinar a primeira inicialização (são iniciadas as variáveis das propriedades do símbolo mutáveis e controladas) e na propriedade do símbolo "índice na janela Observação do Mercado" registramos o índice passado para o construtor.

Como temos a variável m_name na classe base CBaseObj (nela vamos registrar o nome do símbolo), na classe CSymbol é necessário remover a variável m_symbol_name e substituir suas ocorrências por m_name (a atribuição do nome do símbolo acontece no construtor da classe).
Selecionamos qualquer uma das ocorrências do texto "this.m_symbol_name" na listagem da classe CSymbol e pressionamos a combinação de teclas Ctrl+H. É aberta a janela de pesquisa e substituição, nela a entrada que selecionamos no texto já será inserida no campo do valor desejado. No campo de substituição, inserimos this.m_name e na listagem substituímos todas as ocorrências encontradas de nome.m_símbolo_nome por este.m_name.
Também precisamos excluir as variáveis-membro de classe restantes que agora estão no objeto base CBaseObj, e sua presença no CSymbol causa um aviso sobre duplicação de variável durante a compilação. No entanto, nos arquivos anexados ao artigo, todas essas variáveis já estão excluídas — você pode simplesmente fazer o upload dos arquivos e se familiarizar com o seu conteúdo.

No método que retorna a descrição de propriedade inteira, adicionamos a descrição da nova propriedade do símbolo "índice na Observação do Mercado":

//+------------------------------------------------------------------+
//| Return the description of the symbol integer property            |
//+------------------------------------------------------------------+
string CSymbol::GetPropertyDescription(ENUM_SYMBOL_PROP_INTEGER property)
  {
   return
     (
      property==SYMBOL_PROP_STATUS               -- TextByLanguage("Статус","Status")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_INDEX_MW             -- TextByLanguage("Индекс в окне \"Обзор рынка\"","Index in the \"Market Watch window\"")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetStatusDescription()
         )  :
      property==SYMBOL_PROP_CUSTOM               -- TextByLanguage("Пользовательский символ","Custom symbol")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)    -- TextByLanguage("Да","Yes") : TextByLanguage("Нет","No"))
         )  :
      property==SYMBOL_PROP_CHART_MODE           -- TextByLanguage("Тип цены для построения баров","Price type used for generating symbols bars")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetChartModeDescription()
         )  :
      property==SYMBOL_PROP_EXIST                -- TextByLanguage("Символ с таким именем существует","Symbol with this name exists")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)    -- TextByLanguage("Да","Yes") : TextByLanguage("Нет","No"))
         )  :
      property==SYMBOL_PROP_SELECT   -- TextByLanguage("Символ выбран в Market Watch","Symbol is selected in Market Watch")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)    -- TextByLanguage("Да","Yes") : TextByLanguage("Нет","No"))
         )  :
      property==SYMBOL_PROP_VISIBLE  -- TextByLanguage("Символ отображается в Market Watch","Symbol is visible in Market Watch")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)    -- TextByLanguage("Да","Yes") : TextByLanguage("Нет","No"))
         )  :
      property==SYMBOL_PROP_SESSION_DEALS        -- TextByLanguage("Количество сделок в текущей сессии","Number of deals in the current session")+
         (!this.SupportProperty(property)     -- TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_SESSION_BUY_ORDERS   -- TextByLanguage("Общее число ордеров на покупку в текущий момент","Number of Buy orders at the moment")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_SESSION_SELL_ORDERS  -- TextByLanguage("Общее число ордеров на продажу в текущий момент","Number of Sell orders at the moment")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_VOLUME               -- TextByLanguage("Объем в последней сделке","Volume of the last deal")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_VOLUMEHIGH           -- TextByLanguage("Максимальный объём за день","Maximal day volume")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_VOLUMELOW            -- TextByLanguage("Минимальный объём за день","Minimal day volume")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_TIME                 -- TextByLanguage("Время последней котировки","Time of the last quote")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)==0 ? TextByLanguage("(Ещё не было тиков)","(No ticks yet)") : TimeMSCtoString(this.GetProperty(property)))
         )  :
      property==SYMBOL_PROP_DIGITS               -- TextByLanguage("Количество знаков после запятой","Digits after a decimal point")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_DIGITS_LOTS          -- TextByLanguage("Количество знаков после запятой в значении лота","Digits after a decimal point in the value of the lot")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_SPREAD               -- TextByLanguage("Размер спреда в пунктах","Spread value in points")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_SPREAD_FLOAT         -- TextByLanguage("Плавающий спред","Spread is floating")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)    -- TextByLanguage("Да","Yes") : TextByLanguage("Нет","No"))
         )  :
      property==SYMBOL_PROP_TICKS_BOOKDEPTH      -- TextByLanguage("Максимальное количество показываемых заявок в стакане","Maximal number of requests shown in Depth of Market")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else TextByLanguage("Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      property==SYMBOL_PROP_TRADE_CALC_MODE      -- TextByLanguage("Способ вычисления стоимости контракта","Contract price calculation mode")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetCalcModeDescription()
         )  :
      property==SYMBOL_PROP_TRADE_MODE  -- TextByLanguage("Тип исполнения ордеров","Order execution type")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetTradeModeDescription()
         )  :
      property==SYMBOL_PROP_START_TIME           -- TextByLanguage("Дата начала торгов по инструменту","Date of the symbol trade beginning")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
         (this.GetProperty(property)==0  ?  TextByLanguage(": (Отсутствует)",": (Not set)") : ": "+TimeMSCtoString(this.GetProperty(property)*1000))
         )  :
      property==SYMBOL_PROP_EXPIRATION_TIME      -- TextByLanguage("Дата окончания торгов по инструменту","Date of the symbol trade end")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
         (this.GetProperty(property)==0  ?  TextByLanguage(": (Отсутствует)",": (Not set)") : ": "+TimeMSCtoString(this.GetProperty(property)*1000))
         )  :
      property==SYMBOL_PROP_TRADE_STOPS_LEVEL    -- TextByLanguage("Минимальный отступ от цены закрытия для установки Stop ордеров","Minimal indention from the close price to place Stop orders")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_TRADE_FREEZE_LEVEL   -- TextByLanguage("Дистанция заморозки торговых операций","Distance to freeze trade operations in points")+
         (!this.SupportProperty(property)     -- TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_TRADE_EXEMODE        -- TextByLanguage("Режим заключения сделок","Deal execution mode")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetTradeExecDescription()
         )  :
      property==SYMBOL_PROP_SWAP_MODE            -- TextByLanguage("Модель расчета свопа","Swap calculation model")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetSwapModeDescription()
         )  :
      property==SYMBOL_PROP_SWAP_ROLLOVER3DAYS   -- TextByLanguage("День недели для начисления тройного свопа","Day of week to charge 3 days swap rollover")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+DayOfWeekDescription(this.SwapRollover3Days())
         )  :
      property==SYMBOL_PROP_MARGIN_HEDGED_USE_LEG   -- TextByLanguage("Расчет хеджированной маржи по наибольшей стороне","Calculating hedging margin using the larger leg")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+(this.GetProperty(property)    -- TextByLanguage("Да","Yes") : TextByLanguage("Нет","No"))
         )  :
      property==SYMBOL_PROP_EXPIRATION_MODE      -- TextByLanguage("Флаги разрешенных режимов истечения ордера","Flags of allowed order expiration modes")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetExpirationModeFlagsDescription()
         )  :
      property==SYMBOL_PROP_FILLING_MODE         -- TextByLanguage("Флаги разрешенных режимов заливки ордера","Flags of allowed order filling modes")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetFillingModeFlagsDescription()
         )  :
      property==SYMBOL_PROP_ORDER_MODE           -- TextByLanguage("Флаги разрешённых типов ордеров","Flags of allowed order types")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetOrderModeFlagsDescription()
         )  :
      property==SYMBOL_PROP_ORDER_GTC_MODE       -- TextByLanguage("Срок действия StopLoss и TakeProfit ордеров","Expiration of Stop Loss and Take Profit orders")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetOrderGTCModeDescription()
         )  :
      property==SYMBOL_PROP_OPTION_MODE          -- TextByLanguage("Тип опциона","Option type")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetOptionTypeDescription()
         )  :
      property==SYMBOL_PROP_OPTION_RIGHT         -- TextByLanguage("Право опциона","Option right")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
          ": "+this.GetOptionRightDescription()
         )  :
      property==SYMBOL_PROP_BACKGROUND_COLOR     -- TextByLanguage("Цвет фона символа в Market Watch","Background color of the symbol in Market Watch")+
         (!this.SupportProperty(property) ?  TextByLanguage(": Свойство не поддерживается",": Property is not support") :
         #ifdef __MQL5__
         (this.GetProperty(property)==CLR_DEFAULT || this.GetProperty(property)==CLR_NONE  -- TextByLanguage(": (Отсутствует)",": (Not set)") : ": "+::ColorToString((color)this.GetProperty(property),true))
         #else TextByLanguage(": Свойство не поддерживается в MQL4","Property is not supported in MQL4") #endif 
         )  :
      ""
     );
  }
//+------------------------------------------------------------------+

Da listagem da implementação dos métodos da classe CSymbol removemos a segunda forma do método Exist() e o método que retorna o número de casas decimais no valor numérico:

//+------------------------------------------------------------------+
bool CSymbol::Exist(const string name) const
  {
   int total=::SymbolsTotal(false);
   for(int i=0;i<total;i++)
      if(::SymbolName(i,false)==name)
         return true;
   return false;
  }
//+------------------------------------------------------------------+
//| Return the number of decimal places in the 'double' value        |
//+------------------------------------------------------------------+
int CSymbol::GetDigits(const double value) const
  {
   string val_str=(string)value;
   int len=::StringLen(val_str);
   int n=len-::StringFind(val_str,".",0)-1;
   if(::StringSubstr(val_str,len-1,1)=="0")
      n--;
   return n;
  }
//+------------------------------------------------------------------+

Neste caso, esses métodos são supérfluos — Existe() com um parâmetro de entrada nesta classe não é necessário e foi transferido para o arquivo de funções de serviço DELib.mqh, e GetDigits() agora é localizado na classe base CBaseObj.

O método Refresh ()da classe CSymbol é iniciado a partir do nosso temporizador e atualiza todos os dados dos símbolos. No mesmo método, procuraremos alterações nas propriedades do símbolo. Além disso, temos outro método, RefreshRates (), que também inicia do temporizador, mas com uma taxa de atualização mais alta, e neste método são atualizados apenas os dados de cotação do símbolo. Se a pesquisa de alterações nas propriedades do símbolo for feita nos dois métodos, isso levará à duplicação de mensagens sobre eventos.
A solução, nesta situação, seria que o método RefreshRates() atualizará os dados de cotação e retornará um sinalizador indicando seu recebimento bem-sucedido. Esse método será chamado como antes, quer dizer, a partir de seu temporizador, mas também a partir do método Refresh(). Assim, como antes, serão chamados os dois métodos, cada um em seu próprio temporizador, enquanto a busca de alterações nas propriedades do símbolo estará apenas no método Refresh().

Fazemos as alterações necessárias nos métodos RefreshRates() e Refresh():

//+------------------------------------------------------------------+
//| Update quote data by a symbol                                    |
//+------------------------------------------------------------------+
bool CSymbol::RefreshRates(void)
  {
//--- Получение котировочных данных
   ::ResetLastError();
   if(!::SymbolInfoTick(this.m_name,this.m_tick))
     {
      this.m_global_error=::GetLastError();
      return false;
     }
//--- Обновление целочисленных свойств
   this.m_long_prop[SYMBOL_PROP_VOLUME]                                             = (long)this.m_tick.volume;
   this.m_long_prop[SYMBOL_PROP_TIME]                                               = this.TickTime();
//--- Обновление вещественных свойств
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASK)]                              = this.m_tick.ask;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASKHIGH)]                          = ::SymbolInfoDouble(this.m_name,SYMBOL_ASKHIGH);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASKLOW)]                           = ::SymbolInfoDouble(this.m_name,SYMBOL_ASKLOW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BID)]                              = this.m_tick.bid;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BIDHIGH)]                          = this.SymbolBidHigh();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BIDLOW)]                           = this.SymbolBidLow();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LAST)]                             = this.m_tick.last;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LASTHIGH)]                         = ::SymbolInfoDouble(this.m_name,SYMBOL_LASTHIGH);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LASTLOW)]                          = ::SymbolInfoDouble(this.m_name,SYMBOL_LASTLOW);
   return true;
  }  
//+------------------------------------------------------------------+

Aqui primeiro obtemos os dados de cotação para o símbolo e se os dados não puderam ser obtidos, escrevemos o código de erro e saímos do método retornando false. Se os dados foram obtidos, preenchemos as propriedades necessárias do símbolo e retornamos true.

//+------------------------------------------------------------------+
//| Update all symbol data                                           |
//+------------------------------------------------------------------+
void CSymbol::Refresh(void)
  {
//--- Update quote data
   if(!this.RefreshRates())
      return;
#ifdef __MQL5__
   ::ResetLastError();
   if(!this.MarginRates())
     {
      this.m_global_error=::GetLastError();
      return;
     }
#endif 
//--- Prepare event data
   this.m_is_event=false;
   ::ZeroMemory(this.m_struct_curr_symbol);
   this.m_hash_sum=0;
//--- Update integer properties
   this.m_long_prop[SYMBOL_PROP_SELECT]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SELECT);
   this.m_long_prop[SYMBOL_PROP_VISIBLE]                                            = ::SymbolInfoInteger(this.m_name,SYMBOL_VISIBLE);
   this.m_long_prop[SYMBOL_PROP_SESSION_DEALS]                                      = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_DEALS);
   this.m_long_prop[SYMBOL_PROP_SESSION_BUY_ORDERS]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_BUY_ORDERS);
   this.m_long_prop[SYMBOL_PROP_SESSION_SELL_ORDERS]                                = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_SELL_ORDERS);
   this.m_long_prop[SYMBOL_PROP_VOLUMEHIGH]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMEHIGH);
   this.m_long_prop[SYMBOL_PROP_VOLUMELOW]                                          = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMELOW);
   this.m_long_prop[SYMBOL_PROP_SPREAD]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SPREAD);
   this.m_long_prop[SYMBOL_PROP_TICKS_BOOKDEPTH]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_TICKS_BOOKDEPTH);
   this.m_long_prop[SYMBOL_PROP_START_TIME]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_START_TIME);
   this.m_long_prop[SYMBOL_PROP_EXPIRATION_TIME]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_EXPIRATION_TIME);
   this.m_long_prop[SYMBOL_PROP_TRADE_STOPS_LEVEL]                                  = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_STOPS_LEVEL);
   this.m_long_prop[SYMBOL_PROP_TRADE_FREEZE_LEVEL]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_FREEZE_LEVEL);
   this.m_long_prop[SYMBOL_PROP_BACKGROUND_COLOR]                                   = this.SymbolBackgroundColor();

//--- Update real properties
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_PROFIT)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_PROFIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_LOSS)]            = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_LOSS);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_SIZE)]                  = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_CONTRACT_SIZE)]              = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_CONTRACT_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MIN)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MAX)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_STEP)]                      = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_STEP);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_LIMIT)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_LIMIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_LONG)]                        = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_LONG);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_SHORT)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_SHORT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_INITIAL)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_INITIAL);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_MAINTENANCE)]               = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_MAINTENANCE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_VOLUME)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_TURNOVER)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_TURNOVER);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_INTEREST)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_INTEREST);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_BUY_ORDERS_VOLUME)]        = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_BUY_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_SELL_ORDERS_VOLUME)]       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_SELL_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_OPEN)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_OPEN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_CLOSE)]                    = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_CLOSE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_AW)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_AW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_SETTLEMENT)]         = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_SETTLEMENT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MIN)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MAX)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_REAL)]                      = this.SymbolVolumeReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMEHIGH_REAL)]                  = this.SymbolVolumeHighReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMELOW_REAL)]                   = this.SymbolVolumeLowReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_OPTION_STRIKE)]                    = this.SymbolOptionStrike();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_ACCRUED_INTEREST)]           = this.SymbolTradeAccruedInterest();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_FACE_VALUE)]                 = this.SymbolTradeFaceValue();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_LIQUIDITY_RATE)]             = this.SymbolTradeLiquidityRate();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_HEDGED)]                    = this.SymbolMarginHedged();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_INITIAL)]              = this.m_margin_rate.Long.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_INITIAL)]          = this.m_margin_rate.BuyStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_INITIAL)]         = this.m_margin_rate.BuyLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_INITIAL)]     = this.m_margin_rate.BuyStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_MAINTENANCE)]          = this.m_margin_rate.Long.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_MAINTENANCE)]      = this.m_margin_rate.BuyStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_MAINTENANCE)]     = this.m_margin_rate.BuyLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_MAINTENANCE)] = this.m_margin_rate.BuyStopLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_INITIAL)]             = this.m_margin_rate.Short.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_INITIAL)]         = this.m_margin_rate.SellStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_INITIAL)]        = this.m_margin_rate.SellLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_INITIAL)]    = this.m_margin_rate.SellStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_MAINTENANCE)]         = this.m_margin_rate.Short.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_MAINTENANCE)]     = this.m_margin_rate.SellStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_MAINTENANCE)]    = this.m_margin_rate.SellLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_MAINTENANCE)]= this.m_margin_rate.SellStopLimit.Maintenance;
   
//--- Fill in the current symbol data structure
   this.m_struct_curr_symbol.ask                                                    = this.Ask();
   this.m_struct_curr_symbol.ask_high                                               = this.AskHigh();
   this.m_struct_curr_symbol.ask_low                                                = this.AskLow();
   this.m_struct_curr_symbol.bid_last                                               = (this.ChartMode()==SYMBOL_CHART_MODE_BID ? this.Bid() : this.Last());
   this.m_struct_curr_symbol.bid_last_high                                          = (this.ChartMode()==SYMBOL_CHART_MODE_BID ? this.BidHigh() : this.LastHigh());
   this.m_struct_curr_symbol.bid_last_low                                           = (this.ChartMode()==SYMBOL_CHART_MODE_BID ? this.BidLow() : this.LastLow());
   this.m_struct_curr_symbol.volume                                                 = this.Volume();
   this.m_struct_curr_symbol.session_deals                                          = this.SessionDeals();
   this.m_struct_curr_symbol.session_buy_orders                                     = this.SessionBuyOrders();
   this.m_struct_curr_symbol.session_sell_orders                                    = this.SessionSellOrders();
   this.m_struct_curr_symbol.volume_high_day                                        = this.VolumeHigh();
   this.m_struct_curr_symbol.volume_low_day                                         = this.VolumeLow();
   this.m_struct_curr_symbol.spread                                                 = this.Spread();
   this.m_struct_curr_symbol.stops_level                                            = this.TradeStopLevel();
   this.m_struct_curr_symbol.freeze_level                                           = this.TradeFreezeLevel();
   this.m_struct_curr_symbol.volume_limit                                           = this.VolumeLimit();
   this.m_struct_curr_symbol.swap_long                                              = this.SwapLong();
   this.m_struct_curr_symbol.swap_short                                             = this.SwapShort();
   this.m_struct_curr_symbol.session_volume                                         = this.SessionVolume();
   this.m_struct_curr_symbol.session_turnover                                       = this.SessionTurnover();
   this.m_struct_curr_symbol.session_interest                                       = this.SessionInterest();
   this.m_struct_curr_symbol.session_buy_ord_volume                                 = this.SessionBuyOrdersVolume();
   this.m_struct_curr_symbol.session_sell_ord_volume                                = this.SessionSellOrdersVolume();
   this.m_struct_curr_symbol.session_open                                           = this.SessionOpen();
   this.m_struct_curr_symbol.session_close                                          = this.SessionClose();
   this.m_struct_curr_symbol.session_aw                                             = this.SessionAW();
   this.m_struct_curr_symbol.volume_real_day                                        = this.VolumeReal();
   this.m_struct_curr_symbol.volume_high_real_day                                   = this.VolumeHighReal();
   this.m_struct_curr_symbol.volume_low_real_day                                    = this.VolumeLowReal();
   this.m_struct_curr_symbol.option_strike                                          = this.OptionStrike();
   this.m_struct_curr_symbol.trade_mode                                             = this.TradeMode();

//--- Hash sum calculation
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.volume;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.session_deals;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.session_buy_orders;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.session_sell_orders;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.volume_high_day;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.volume_low_day;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.spread;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.stops_level;
   this.m_hash_sum+=(double)this.m_struct_curr_symbol.freeze_level;
   this.m_hash_sum+=this.m_struct_curr_symbol.ask;
   this.m_hash_sum+=this.m_struct_curr_symbol.ask_high;
   this.m_hash_sum+=this.m_struct_curr_symbol.ask_low;
   this.m_hash_sum+=this.m_struct_curr_symbol.bid_last;
   this.m_hash_sum+=this.m_struct_curr_symbol.bid_last_high;
   this.m_hash_sum+=this.m_struct_curr_symbol.bid_last_low;
   this.m_hash_sum+=this.m_struct_curr_symbol.volume_limit;
   this.m_hash_sum+=this.m_struct_curr_symbol.swap_long;
   this.m_hash_sum+=this.m_struct_curr_symbol.swap_short;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_volume;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_turnover;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_interest;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_buy_ord_volume;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_sell_ord_volume;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_open;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_close;
   this.m_hash_sum+=this.m_struct_curr_symbol.session_aw;
   this.m_hash_sum+=this.m_struct_curr_symbol.volume_real_day;
   this.m_hash_sum+=this.m_struct_curr_symbol.volume_high_real_day;
   this.m_hash_sum+=this.m_struct_curr_symbol.volume_low_real_day;
   this.m_hash_sum+=this.m_struct_curr_symbol.option_strike;
   this.m_hash_sum+=this.m_struct_curr_symbol.trade_mode;

//--- First launch
   if(this.m_struct_prev_symbol.trade_mode==WRONG_VALUE)
     {
      this.m_struct_prev_symbol=this.m_struct_curr_symbol;
      this.m_hash_sum_prev=this.m_hash_sum;
      return;
     }
//--- If symbol's hash sum changed
   if(this.m_hash_sum!=this.m_hash_sum_prev)
     {
      this.m_event_code=this.SetEventCode();
      this.SetTypeEvent();
      CEventBaseObj *event=this.GetEvent(WRONG_VALUE,false);
      if(event!=NULL)
        {
         ENUM_SYMBOL_EVENT event_id=(ENUM_SYMBOL_EVENT)event.ID();
         if(event_id!=SYMBOL_EVENT_NO_EVENT)
           {
            this.m_is_event=true;
           }
        }
      this.m_hash_sum_prev=this.m_hash_sum;
     }
  }
//+------------------------------------------------------------------+

Neste caso, primeiro chamamos o método RefreshRates() e se não foi possível obter dados de cotação, não faz sentido obter o restante dos dados - saímos do método.
Depois, redefinimos o sinalizador de evento, zeramos a estrutura do estado atual das propriedades do símbolo e zeramos o valor atual de hash. Em seguida, preenchemos todas as propriedades do símbolo com dados atuais e armazenamos esses dados na estrutura do estado atual das propriedades do símbolo. Depois de preencher a estrutura calculamos a soma de hash atual.
Se esta for a primeira inicialização (propriedade do símbolo SYMBOL_TRADE_MODE definido como WRONG_VALUE), na estrutura do estado anterior do valor armazenaremos a estrutura do estado atual , no último valor do hash, escrevemos a soma de hash atual e saímos do método.
Se esta não for a primeira execução, precisaremos verificar se há desigualdade no valor das somas de hash passadas e atuais.
Se o valor de hash mudou
significa que houve alguma alteração nas propriedades do símbolo, portanto, chamamos o método para definir o código do evento, o método para receber o evento a partir do código de evento e o registro de evento na lista de eventos que ocorreram, obtemos o último evento dos eventos recém adicionados da lista, verificamos o tipo de eventoe se não for "Não há evento", tiramos o sinalizador de evento. Por fim, armazenamos o valor de hash atual como no anterior para verificações adicionais.

Isso conclui o aprimoramento da classe CSymbol para procurar eventos e trabalhar com o novo objeto base.

A classe de objeto-símbolo está pronta. Agora, cada símbolo pode rastrear seus eventos e colocá-los em sua lista de eventos. Usamos uma coleção de símbolos, por isso, precisamos percorrer todos os símbolos da coleção e obter sua lista de eventos a partir de cada um deles. Também precisamos colocar todos esses eventos na lista de eventos da coleção (agora a coleção também possui essa lista, pois está localizada no objeto base CBaseObj). Sendo assim, resta pesquisar a lista resultante de eventos para determinar eventos para cada um dos símbolos da coleção.

Também podemos trabalhar com a janela "Observação do Mercado" (para isso implementamos o acompanhamento de eventos), adicionando/removendo/classificando símbolos na janela Observação do mercado. Para esses fins, precisaremos armazenar uma cópia da janela "Observação do Mercado" e a soma de hash dos símbolos localizados nela. Quando a soma de hash for alterada, entenderemos que na Observação do Mercado ocorreu um evento, assim, basta determinar o tipo de evento, comparando o estado atual na janela Observação do Mercado com seu molde e enviar o evento identificado ao programa de controle.

Abrimos o arquivo de classe da coleção de símbolos SymbolsCollection.mqh e fazemos as alterações necessárias:

//+------------------------------------------------------------------+
//|                                            SymbolsCollection.mqh |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
//+------------------------------------------------------------------+
//| Include files                                                    |
//+------------------------------------------------------------------+
#include <Arrays\ArrayString.mqh>
#include "ListObj.mqh"
#include "..\Services\Select.mqh"
#include "..\Objects\Symbols\Symbol.mqh"
#include "..\Objects\Symbols\SymbolFX.mqh"
#include "..\Objects\Symbols\SymbolFXMajor.mqh"
#include "..\Objects\Symbols\SymbolFXMinor.mqh"
#include "..\Objects\Symbols\SymbolFXExotic.mqh"
#include "..\Objects\Symbols\SymbolFXRub.mqh"
#include "..\Objects\Symbols\SymbolMetall.mqh"
#include "..\Objects\Symbols\SymbolIndex.mqh"
#include "..\Objects\Symbols\SymbolIndicative.mqh"
#include "..\Objects\Symbols\SymbolCrypto.mqh"
#include "..\Objects\Symbols\SymbolCommodity.mqh"
#include "..\Objects\Symbols\SymbolExchange.mqh"
#include "..\Objects\Symbols\SymbolFutures.mqh"
#include "..\Objects\Symbols\SymbolCFD.mqh"
#include "..\Objects\Symbols\SymbolStocks.mqh"
#include "..\Objects\Symbols\SymbolBonds.mqh"
#include "..\Objects\Symbols\SymbolOption.mqh"
#include "..\Objects\Symbols\SymbolCollateral.mqh"
#include "..\Objects\Symbols\SymbolCustom.mqh"
#include "..\Objects\Symbols\SymbolCommon.mqh"
//+------------------------------------------------------------------+
//| Symbol collection                                                |
//+------------------------------------------------------------------+
class CSymbolsCollection : public CBaseObj
  {
private:
   CListObj          m_list_all_symbols;                          // The list of all symbol objects
   CArrayString      m_list_names;                                // Symbol name control list
   ENUM_SYMBOLS_MODE m_mode_list;                                 // Mode of working with symbol lists
   ENUM_SYMBOL_EVENT m_last_event;                                // The last event
   string            m_array_symbols[];                           // The array of used symbols passed from the program
   int               m_delta_symbol;                              // Difference in the number of symbols compared to the previous check
   int               m_total_symbols;                             // Number of symbols in the Market Watch window
   int               m_total_symbol_prev;                         // Number of symbols in the Market Watch window during the previous check
//--- Return the flag of a symbol object presence by its name in the (1) list of all symbols, (2) Market Watch window, (3) control list
   bool              IsPresentSymbolInList(const string symbol_name);
   bool              IsPresentSymbolInMW(const string symbol_name);
   bool              IsPresentSymbolInControlList(const string symbol_name);
//--- Create the symbol object and place it to the list
   bool              CreateNewSymbol(const ENUM_SYMBOL_STATUS symbol_status,const string name,const int index);
//--- Return the (1) type of a used symbol list (Market watch/Server),
//--- (2) the number of visible symbols, (3) symbol index in the Market Watch window
   ENUM_SYMBOLS_MODE TypeSymbolsList(const string &symbol_used_array[]);
   int               SymbolsTotalVisible(void)                    const;
   int               SymbolIndexInMW(const string name)           const;
   
//--- Define a symbol affiliation with a group by name and return it
   ENUM_SYMBOL_STATUS SymbolStatus(const string symbol_name)      const;
//--- Return a symbol affiliation with a category by custom criteria
   ENUM_SYMBOL_STATUS StatusByCustomPredefined(const string symbol_name)  const;
//--- Return a symbol affiliation with categories by margin calculation
   ENUM_SYMBOL_STATUS StatusByCalcMode(const string symbol_name)  const;
//--- Return a symbol affiliation with pre-defined (1) majors, (2) minors, (3) exotics, (4) RUB,
//--- (5) indicatives, (6) metals, (7) commodities, (8) indices, (9) cryptocurrency, (10) options
   bool              IsPredefinedFXMajor(const string name)       const;
   bool              IsPredefinedFXMinor(const string name)       const;
   bool              IsPredefinedFXExotic(const string name)      const;
   bool              IsPredefinedFXRUB(const string name)         const;
   bool              IsPredefinedIndicative(const string name)    const;
   bool              IsPredefinedMetall(const string name)        const;
   bool              IsPredefinedCommodity(const string name)     const;
   bool              IsPredefinedIndex(const string name)         const;
   bool              IsPredefinedCrypto(const string name)        const;
   bool              IsPredefinedOption(const string name)        const;

public:
//--- Return the full collection list 'as is'
   CArrayObj        *GetList(void)                                                                          { return &this.m_list_all_symbols;                                      }
//--- Return the list by selected (1) integer, (2) real and (3) string properties meeting the compared criterion
   CArrayObj        *GetList(ENUM_SYMBOL_PROP_INTEGER property,long value,ENUM_COMPARER_TYPE mode=EQUAL)    { return CSelect::BySymbolProperty(this.GetList(),property,value,mode); }
   CArrayObj        *GetList(ENUM_SYMBOL_PROP_DOUBLE property,double value,ENUM_COMPARER_TYPE mode=EQUAL)   { return CSelect::BySymbolProperty(this.GetList(),property,value,mode); }
   CArrayObj        *GetList(ENUM_SYMBOL_PROP_STRING property,string value,ENUM_COMPARER_TYPE mode=EQUAL)   { return CSelect::BySymbolProperty(this.GetList(),property,value,mode); }
//--- Return the (1) symbol object, (2) the symbol object index from the list by a name
   CSymbol          *GetSymbolByName(const string name);
   int               GetSymbolIndexByName(const string name);
//--- Return the number of new symbols in the Market Watch window
   int               NewSymbols(void)    const                                                              { return this.m_delta_symbol;                                           }
//--- Return (1) the mode of working with symbol lists, (2) the event flag and (3) the event of one of the collection symbols
   ENUM_SYMBOLS_MODE ModeSymbolsList(void)                        const                                     { return this.m_mode_list;                                              }
   bool              IsEvent(void)                                const                                     { return this.m_is_event;                                               }
   int               GetLastEventsCode(void)                      const                                     { return this.m_event_code;                                             }
   ENUM_SYMBOL_EVENT GetLastEvent(void)                           const                                     { return this.m_last_event;                                             }
//--- Return the number of symbols in the collection
   int               GetSymbolsCollectionTotal(void)              const                                     { return this.m_list_all_symbols.Total();                               }

//--- Constructor
                     CSymbolsCollection();
   
//--- (1) Set the list of used symbols, (2) creating the symbol list (Market Watch or the complete list)
   bool              SetUsedSymbols(const string &symbol_used_array[]);
   bool              CreateSymbolsList(const bool flag);
//--- Save names of used Market Watch symbols
   void              CopySymbolsNames(void);
//--- Update (1) all, (2) quote data of the collection symbols
   virtual void      Refresh(void);
   void              RefreshRates(void);
//--- Working with the events of the (1) collection symbol list, (2) market watch window
   void              SymbolsEventsControl(void);
   void              MarketWatchEventsControl(const bool send_events=true);
//--- Return the description of the (1) Market Watch window event, (2) mode of working with symbols
   string            EventDescription(const ENUM_SYMBOL_EVENT event);
   string            ModeSymbolsListDescription(void);
  };
//+------------------------------------------------------------------+

Para criar o molde da janela "Observação do Mercado", vamos usar o arquivo da classe CArrayString incluído a partir da biblioteca padrão. Nesta lista, armazenaremos uma cópia do conjunto de símbolo da Observação do Mercado e compararemos o estado atual da lista de símbolos na janela com o estado atual da lista de símbolos no molde. Se acontecerem alterações, responderemos a elas para criar um evento da janela "Observação do Mercado".

Para a variável m_last_event, armazenaremos o último evento ocorrido com qualquer um dos símbolos da coleção. Assim, a variável armazenará o evento mais recente ocorrido num dos símbolos usados.
O array m_array_symbols serve para passar para a classe uma coleção de símbolos do programa do controle do array de símbolos usados no programa.
Nas variáveis-membro da classe m_total_symbols e m_total_symbols_prev armazenaremos o número de símbolos atual e anterior na janela "Observação do Mercado". A comparação dos valores destas variáveis permite conhecer os eventos de adição/remoção de símbolos na Observação do Mercado.

Os métodos privados da classe IsPresentSymbolInMW() e IsPresentSymbolInControlList() retornam os sinalizadores indicando se o símbolo existe na janela "Observação do Mercado" e na lista-molde dessa mesma janela de acordo com o seu nome. Já os métodos SymbolsTotalVisible() e SymbolIndexInMW() retornam o número de símbolos visíveis na janela "Observação do Mercado" e o índice do símbolo na lista desta janela, respectivamente.

Na seção pública da classe, inseriremos os métodos:
IsEvent() — retorna o sinalizador que indica se existe algum evento na coleção de símbolos ou na janela "Observação do Mercado",
GetLastEventsCode() — retorna o código do último evento na coleção de símbolos ou na janela "Observação do Mercado",
GetLastEvent() — retorna o último evento na coleção de símbolos ou na janela "Observação do Mercado",
GetSymbolsCollectionTotal() — retorna o número total de símbolos na coleção,
CreateSymbolsList() — cria uma lista de coleções ao usar a janela "Observação do Mercado" ou ao implementar a lista de símbolos completa no servidor (não mais que 1000),
CopySymbolsNames() — cria um molde de símbolos da janela "Observação Mercado" a partir da janela de todos os símbolos da coleção,
Refresh() — agora o método é declarado como virtual, uma vez que ele é declarado como virtual na classe do objeto base (já a coleção de símbolos agora é criada com base na classe do objeto base CBaseObj),
SymbolsEventsControl() — método para trabalhar com uma lista de coleção de símbolos a fim de determinar eventos da coleção de símbolos,
MarketWatchEventsControl() — método para trabalhar com uma lista da janela "Observação do Mercado" a fim de determinar eventos na janela "Observação do Mercado",
EventDescription() — retorna a descrição do evento da coleção de símbolos,
ModeSymbolsListDescription() — retorna a descrição do modo de trabalho com símbolos.

Consideremos a implementação de métodos.
No construtor da classe, em sua lista de inicialização, iniciamos as variáveis para trabalhar com a janela "Observação do Mercado" e, no corpo da classe, substituímos a classificação da lista de símbolos de coleção segundo o nome pela classificação segundo o índice na janela "Observação do Mercado" e limpamos a lista-molde da janela "Observação do Mercado".

//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CSymbolsCollection::CSymbolsCollection(void) : m_total_symbol_prev(0),
                                               m_delta_symbol(0),
                                               m_mode_list(SYMBOLS_MODE_CURRENT)
  {
   this.m_list_all_symbols.Sort(SORT_BY_SYMBOL_INDEX_MW);
   this.m_list_all_symbols.Clear();
   this.m_list_all_symbols.Type(COLLECTION_SYMBOLS_ID);
   this.m_list_names.Clear();
  }
//+------------------------------------------------------------------+

Como na janela "Observação do Mercado", o símbolo pode estar, mas não ser exibido (propriedade do símbolo SYMBOL_VISIBLE — alguns símbolos (como regra, são pares de moedas para calcular os requisitos de margem e lucro na moeda de depósito) são selecionados automaticamente, mas podem não ser exibidos na Observação do Mercado), para conhecer apenas o número de símbolos visíveis, precisamos percorrer os símbolos da janela para contar apenas aqueles para os quais esta propriedade está definida.
O método SymbolsTotalVisible() retorna o número de símbolos visíveis na janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Return the number of visible symbols in the Market Watch window  |
//+------------------------------------------------------------------+
int CSymbolsCollection::SymbolsTotalVisible(void) const
  {
   int total=::SymbolsTotal(true),n=0;
   for(int i=0;i<total;i++)
     {
      if(!::SymbolInfoInteger(::SymbolName(i,true),SYMBOL_VISIBLE))
         continue;
      n++;
     }
   return n;
  }
//+------------------------------------------------------------------+

Método que retorna o índice do símbolo na lista da janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Return symbol index in the Market Watch window                   |
//+------------------------------------------------------------------+
int CSymbolsCollection::SymbolIndexInMW(const string name) const
  {
   int total=::SymbolsTotal(true);
   for(int i=0;i<total;i++)
     {
      if(!::SymbolInfoInteger(::SymbolName(i,true),SYMBOL_VISIBLE))
         continue;
      if(SymbolName(i,true)==name)
         return i;
     }
   return WRONG_VALUE;
  }
//+------------------------------------------------------------------+

Ao trabalhar com a lista de símbolos da janela "Observação do Mercado", precisamos conhecer o índice de cada um dos símbolos na lista da janela para que possamos sincronizar o local dos símbolos na lista de símbolos de coleção com o local dos símbolos na janela "Observação do Mercado". Por exemplo, isso pode ser útil para criar uma janela da lista de símbolos própria que esteja totalmente sincronizada com a janela do terminal. O índice será uma das propriedades do símbolo, o que permitirá classificar a lista por essa propriedade. O índice será passado ao construtor da classe de símbolo abstrato.

Método que retorna o sinalizador que indica que do símbolo visível está na janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Return the visible symbol object presence flag                   |
//| by its name in the Market Watch window                           |
//+------------------------------------------------------------------+
bool CSymbolsCollection::IsPresentSymbolInMW(const string symbol_name)
  {
   int total=SymbolsTotal(true);
   for(int i=0;i<total;i++)
     {
      string name=::SymbolName(i,true);
      if(!::SymbolInfoInteger(name,SYMBOL_VISIBLE))
         continue;
      if(name==symbol_name)
         return true;
     }
   return false;
  }
//+------------------------------------------------------------------+

Para o método é transferido o nome do símbolo, no ciclo da lista completa de símbolos, selecionados na janela "Observação do Mercado", ignoramos o símbolo invisível, comparamos o nome do próximo símbolo com o do transferido para o método, e, se o nome coincidir, retornamos true. Se o símbolo não for encontrado na lista, retornamos false.

Método que retorna o sinalizador que o símbolo está na lista-molde da janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Return the flag of a symbol object presence in the control list  |
//+------------------------------------------------------------------+
bool CSymbolsCollection::IsPresentSymbolInControlList(const string symbol_name)
  {
   int total=this.m_list_names.Total();
   for(int i=0;i<total;i++)
     {
      string name=this.m_list_names.At(i);
      if(name==NULL)
         continue;
      if(name==symbol_name)
         return true;
     }
   return false;
  }
//+------------------------------------------------------------------+

O nome do símbolo procurado é passado para o método. No ciclo da lista-molde da janela Observação do Mercado, nós temos o próximo símbolo e se o nome corresponder ao nome transferido para o método, retornamos true, caso contrário, false.

Método para criar uma lista ao trabalhar com a janela "Observação do Mercado" ou com uma lista completa de símbolos no servidor:

//+------------------------------------------------------------------+
//| Creating the symbol list (Market Watch or the complete list)     |
//+------------------------------------------------------------------+
bool CSymbolsCollection::CreateSymbolsList(const bool flag)
  {
   bool res=true;
   int total=::SymbolsTotal(flag);
   for(int i=0;i<total && i<SYMBOLS_COMMON_TOTAL;i++)
     {
      string name=::SymbolName(i,flag);
      if(flag && !::SymbolInfoInteger(name,SYMBOL_VISIBLE))
         continue;
      ENUM_SYMBOL_STATUS status=this.SymbolStatus(name);
      bool add=this.CreateNewSymbol(status,name,i);
      res &=add;
      if(!add) 
         continue;
     }
   return res;
  }
//+------------------------------------------------------------------+

Para o método é transferido o sinalizador que define o modo de pesquisa: true — trabalho com os símbolos selecionados na janela "Observação do Mercado", false — trabalho com uma lista completa de símbolos disponíveis no servidor. Obtemos o número total de símbolos dependendo do sinalizador — na janela "Observação do Mercado", no servidor, e no ciclo pela lista, mas não mais que o valor especificado pela constante SYMBOLS_COMMON_TOTAL no arquivo Defines.mqh (1000 símbolos) obtemos o nome do próximo símbolo da lista, verificamos sua propriedade de visibilidade sob a condição de trabalhar com a janela "Observação do Mercado", e se o símbolo não estiver visível, vamos ignorá-lo.
Em seguida, obtemos o estado do objeto do símbolo pelo seu nome e adicionamos o símbolo à lista completa de símbolos da coleção usando o método CreateNewSymbol(), que consideramos no artigo anterior. (Observe que o método foi ligeiramente alterado, pois foi adicionada uma nova propriedade de símbolo — seu índice na lista de símbolos da janela "Observação do mercado" —, agora para o objeto-símbolo também é transferido o índice)
Na variável que retorna o resultado do método, são inseridos os resultados da adição de cada símbolo à toda a lista de símbolos da coleção
, e o valor final dessa variável é retornado do método no final de todo o ciclo de processamento de símbolos.

Consideremos o método aprimorado para criar um objeto-símbolo e colocá-lo numa lista:

//+------------------------------------------------------------------+
//| Create a symbol object and place it to the list                  |
//+------------------------------------------------------------------+
bool CSymbolsCollection::CreateNewSymbol(const ENUM_SYMBOL_STATUS symbol_status,const string name,const int index)
  {
   if(this.IsPresentSymbolInList(name))
     {
      return true;
     }
   if(#ifdef __MQL5__ !::SymbolInfoInteger(name,SYMBOL_EXIST) #else !Exist(name) #endif )
     {
      string t1=TextByLanguage("Ошибка входных данных: нет символа ","Input error: no ");
      string t2=TextByLanguage(" на сервере"," symbol on the server");
      ::Print(DFUN,t1,name,t2);
      this.m_global_error=ERR_MARKET_UNKNOWN_SYMBOL;
      return false;
     }
   CSymbol *symbol=NULL;
   switch(symbol_status)
     {
      case SYMBOL_STATUS_FX         :  symbol=new CSymbolFX(name,index);         break;   // Forex symbol
      case SYMBOL_STATUS_FX_MAJOR   :  symbol=new CSymbolFXMajor(name,index);    break;   // Major Forex symbol
      case SYMBOL_STATUS_FX_MINOR   :  symbol=new CSymbolFXMinor(name,index);    break;   // Minor Forex symbol
      case SYMBOL_STATUS_FX_EXOTIC  :  symbol=new CSymbolFXExotic(name,index);   break;   // Exotic Forex symbol
      case SYMBOL_STATUS_FX_RUB     :  symbol=new CSymbolFXRub(name,index);      break;   // Forex symbol/RUR
      case SYMBOL_STATUS_METAL      :  symbol=new CSymbolMetall(name,index);     break;   // Metal
      case SYMBOL_STATUS_INDEX      :  symbol=new CSymbolIndex(name,index);      break;   // Index
      case SYMBOL_STATUS_INDICATIVE :  symbol=new CSymbolIndicative(name,index); break;   // Indicative
      case SYMBOL_STATUS_CRYPTO     :  symbol=new CSymbolCrypto(name,index);     break;   // Cryptocurrency symbol
      case SYMBOL_STATUS_COMMODITY  :  symbol=new CSymbolCommodity(name,index);  break;   // Commodity
      case SYMBOL_STATUS_EXCHANGE   :  symbol=new CSymbolExchange(name,index);   break;   // Exchange symbol
      case SYMBOL_STATUS_FUTURES    :  symbol=new CSymbolFutures(name,index);    break;   // Futures
      case SYMBOL_STATUS_CFD        :  symbol=new CSymbolCFD(name,index);        break;   // CFD
      case SYMBOL_STATUS_STOCKS     :  symbol=new CSymbolStocks(name,index);     break;   // Stock
      case SYMBOL_STATUS_BONDS      :  symbol=new CSymbolBonds(name,index);      break;   // Bond
      case SYMBOL_STATUS_OPTION     :  symbol=new CSymbolOption(name,index);     break;   // Option
      case SYMBOL_STATUS_COLLATERAL :  symbol=new CSymbolCollateral(name,index); break;   // Non-tradable asset
      case SYMBOL_STATUS_CUSTOM     :  symbol=new CSymbolCustom(name,index);     break;   // Custom symbol
      default                       :  symbol=new CSymbolCommon(name,index);     break;   // The rest
     }
   if(symbol==NULL)
     {
      ::Print(DFUN,TextByLanguage("Не удалось создать объект-символ ","Failed to create symbol object "),name);
      return false;
     }
   if(!this.m_list_all_symbols.Add(symbol))
     {
      string t1=TextByLanguage("Не удалось добавить символ ","Failed to add ");
      string t2=TextByLanguage(" в список"," symbol to the list");
      ::Print(DFUN,t1,name,t2);
      delete symbol;
      return false;
     }
   return true;
  }
//+------------------------------------------------------------------+

Como se pode ver na listagem, também passamos um índice para o método e enviamos cada índice junto com o nome do símbolo para cada uma das classes construtoras de objetos-símbolo. Por conseguinte, é necessário um refinamento de cada uma das classes herdeiras da classe do símbolo abstrato CSymbol.
Consideremos esta modificação usando a classe CSymbolFX como exemplo:

//+------------------------------------------------------------------+
//|                                                     SymbolFX.mqh |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
//+------------------------------------------------------------------+
//| Include files                                                    |
//+------------------------------------------------------------------+
#include "Symbol.mqh"
//+------------------------------------------------------------------+
//| Forex symbol                                                     |
//+------------------------------------------------------------------+
class CSymbolFX : public CSymbol
  {
public:
//--- Constructor
                     CSymbolFX(const string name,const int index) : CSymbol(SYMBOL_STATUS_FX,name,index) {}
//--- Supported integer properties of a symbol
   virtual bool      SupportProperty(ENUM_SYMBOL_PROP_INTEGER property);
//--- Supported real properties of a symbol
   virtual bool      SupportProperty(ENUM_SYMBOL_PROP_DOUBLE property);
//--- Supported string properties of a symbol
   virtual bool      SupportProperty(ENUM_SYMBOL_PROP_STRING property);
//--- Display a short symbol description in the journal
   virtual void      PrintShort(void);
  };
//+------------------------------------------------------------------+

Neste caso, apenas para o construtor da classe, junto com o nome do símbolo, é transferido seu índice, e na lista de inicialização para o construtor de classe pai CSymbol também passamos este índice.
Isso é tudo o que precisa ser alterado em todas as classes herdeiras de um símbolo abstrato. Nos arquivos anexados no final do artigo, já foram feitas todas as alterações nas classes de objetos de símbolo.

Método modificado que define a lista de símbolos usados na coleção:

//+------------------------------------------------------------------+
//| Set the list of used symbols                                     |
//+------------------------------------------------------------------+
bool CSymbolsCollection::SetUsedSymbols(const string &symbol_used_array[])
  {
   ::ArrayCopy(this.m_array_symbols,symbol_used_array);
   this.m_mode_list=this.TypeSymbolsList(this.m_array_symbols);
   this.m_list_all_symbols.Clear();
   this.m_list_all_symbols.Sort(SORT_BY_SYMBOL_INDEX_MW);
   //--- Use only the current symbol
   if(this.m_mode_list==SYMBOLS_MODE_CURRENT)
     {
      string name=::Symbol();
      ENUM_SYMBOL_STATUS status=this.SymbolStatus(name);
      return this.CreateNewSymbol(status,name,this.SymbolIndexInMW(name));
     }
   else
     {
      bool res=true;
      //--- Use the pre-defined symbol list
      if(this.m_mode_list==SYMBOLS_MODE_DEFINES)
        {
         int total=::ArraySize(this.m_array_symbols);
         for(int i=0;i<total;i++)
           {
            string name=this.m_array_symbols[i];
            ENUM_SYMBOL_STATUS status=this.SymbolStatus(name);
            bool add=this.CreateNewSymbol(status,name,this.SymbolIndexInMW(name));
            res &=add;
            if(!add) 
               continue;
           }
         return res;
        }
      //--- Use the full list of the server symbols
      else if(this.m_mode_list==SYMBOLS_MODE_ALL)
        {
         return this.CreateSymbolsList(false);
        }
      //--- Use the symbol list from the Market Watch window
      else if(this.m_mode_list==SYMBOLS_MODE_MARKET_WATCH)
        {
         this.MarketWatchEventsControl(false);
         return true;
        }
     }
   return false;
  }
//+------------------------------------------------------------------+

Neste caso, para o array correspondente imediatamente copiamos o array de símbolos transferido do programa de controle. Preenchemos o modo para trabalhar com símbolos, definimos a classificação de toda a lista de símbolos no modo de classificação por índice. Agora, para o método de criação de novo objeto-símbolo transferimos, além do nome do símbolo, seu índice.
Ao usar a lista completa de símbolos no servidor, chamamos o método de construção de lista de símbolos de coleção com o sinalizador = false, o que indica a construção de uma lista completa de símbolo no servidor,
já ao usar uma lista da janela "Observação do Mercado", chamamos o método de trabalhar com a janela "Observação do Mercado" com sinalizador = false, o que não significa uma proibição para o método de trabalhar com eventos, mas apenas um requisito para criar uma lista e lembrar seus dados.

Método para trabalhar com eventos de todos os símbolos da coleção:

//+------------------------------------------------------------------+
//| Working with the events of the collection symbol list            |
//+------------------------------------------------------------------+
void CSymbolsCollection::SymbolsEventsControl(void)
  {
   this.m_is_event=false;     
   this.m_list_events.Clear();
   this.m_list_events.Sort(); 
   //--- The full update of all collection symbols
   int total=this.m_list_all_symbols.Total();
   for(int i=0;i<total;i++)
     {
      CSymbol *symbol=this.m_list_all_symbols.At(i);
      if(symbol==NULL)
         continue;
      symbol.Refresh();
      if(!symbol.IsEvent())
         continue;
      this.m_is_event=true;
      CArrayObj *list=symbol.GetListEvents();
      if(list==NULL)
         continue;
      this.m_event_code=symbol.GetEventCode();
      int n=list.Total();
      for(int j=0; j<n; j++)
        {
         CEventBaseObj *event=list.At(j);
         if(event==NULL)
            continue;
         ENUM_SYMBOL_EVENT event_id=(ENUM_SYMBOL_EVENT)event.ID();
         if(event_id==SYMBOL_EVENT_NO_EVENT)
            continue;
         this.m_last_event=event_id;
         if(this.EventAdd((ushort)event.ID(),event.LParam(),event.DParam(),event.SParam()))
           {
            ::EventChartCustom(this.m_chart_id,(ushort)event_id,event.LParam(),event.DParam(),event.SParam());
           }
        }
     }
  }
//+------------------------------------------------------------------+

Este método funciona no temporizador. Primeiro são inicializados os dados:
é redefinido o sinalizadorde evento na coleção de símbolos,   
a lista de eventos na coleção de símbolos é limpa e   
para a lista é definido o sinalizador da lista classificada.
Em seguida, no ciclo de todos os símbolos, que estão na lista de símbolos da coleção, obtemos o próximo símbolo, atualizamos todos seus dados e verificamos se existe o sinalizador de evento definido para o símbolo. Se não houver evento, prosseguimos com a verificação do próximo símbolo na coleção.
Se no símbolo estiver definido o sinalizador do evento, definimos o sinalizador de evento para toda a coleção (presença de evento, pelo menos um dos símbolos é a presença do evento para toda a coleção). Obtemos a lista de todos os eventos do símbolo atual, definimos o código do último evento da coleção igual ao código do evento do símbolo atual da lista, e, se houver evento, no próximo símbolo será atualizado o valor salvo na variável que armazena o último valor da coleção, e no ciclo da lista de todos os eventos do símbolo atual obtemos o próximo evento e
salvamos o identificador do evento como o último evento na coleção. Da mesma maneira, o próximo evento de símbolo atualiza o último evento de coleção de símbolos.
Em seguida, criamos um evento de coleção com os parâmetros definidos a partir do evento do símbolo ( identificador do evento, parâmetro long, parâmetro double e parâmetro de string do evento) e salvamos o evento do símbolo na lista de eventos da coleção de símbolos.
Se o evento do símbolo for salvo com sucesso na lista de eventos da coleção, este um evento será enviado para o gráfico do programa usando a função EventChartCustom() com os mesmos parâmetros de evento para processamento adicional do evento no programa de chamada.

Assim, ao receber uma lista de eventos de cada um dos símbolos da lista de coleções, passamos pela lista de eventos de cada símbolo e registramos todos os seus eventos na lista de eventos da coleção. Após a conclusão do ciclo, a lista de eventos da coleção conterá todos os eventos de todos os símbolos da coleção e, para cada um dos eventos de cada símbolo da coleção, será criado um evento e enviado para o gráfico do programa de controle.

Para reconhecer eventos na janela "Observação do Mercado", precisamos calcular a soma de todos os símbolos na janela "Observação do Mercado". Sua mudança nos sinalizará sobre o evento que aconteceu. A primeira coisa que vem à mente é uma contagem simples do número de símbolos na janela, mas ... Adicionar ou remover um símbolo aumentará ou diminuirá o tamanho da lista, mas a classificação dos símbolo com o mouse não alterará o número de símbolos. Isso significa que o número de símbolos na janela "Observação do Mercado" não é adequado para calcular o valor do hash.
Fazemos o seguinte: cada símbolo armazenado na lista — seu nome pode ser representado como um número (código do símbolo), que é a soma dos valores uchar dos códigos de símbolos (letras) que compõem o nome do símbolo, com a adição do índice do símbolo para esse valor à Lista da janela Observação do Mercado. A soma de hash será a soma de todos os códigos de símbolos.

  • A adição de um símbolo à lista alterará a soma de hash (o novo código do símbolo será adicionado à soma de hash).
  • A remoção de um símbolo da lista alterará a soma de hash (o código do símbolo excluído será subtraído da soma do hash).
  • A classificação de uma lista de símbolos alterará a soma de hash (os códigos dos símbolo classificados serão alterados conforme os índices serão alterados)

Implementação do método para trabalhar com eventos da janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Working with market watch window events                          |
//+------------------------------------------------------------------+
void CSymbolsCollection::MarketWatchEventsControl(const bool send_events=true)
  {
   ::ResetLastError();
//--- If no current prices are received, exit
   if(!::SymbolInfoTick(::Symbol(),this.m_tick))
     {
      this.m_global_error=::GetLastError();
      return;
     }
   uchar array[];
   int sum=0;
   this.m_hash_sum=0;
//--- Calculate the hash sum of all visible symbols in the Market Watch window
   this.m_total_symbols=this.SymbolsTotalVisible();
   //--- In the loop by all Market Watch window symbols
   int total_symbols=::SymbolsTotal(true);
   for(int i=0;i<total_symbols;i++)
     {
      //--- get a symbol name by index
      string name=::SymbolName(i,true);
      //--- skip if invisible
      if(!::SymbolInfoInteger(name,SYMBOL_VISIBLE))
         continue;
      //--- write symbol name (characters) codes to the uchar array
      ::StringToCharArray(name,array);
      //--- in a loop by the resulting array, sum up the values of all array cells creating the symbol code
      for(int j=::ArraySize(array)-1;j>WRONG_VALUE;j--)
         sum+=array[j];
      //--- add the symbol code and the loop index specifying the symbol index in the market watch list to the hash sum
      m_hash_sum+=i+sum;
     }
//--- If sending events is disabled, create the collection list and exit saving the current hash some as the previous one
   if(!send_events)
     {
      //--- Clear the list
      this.m_list_all_symbols.Clear();
      //--- Clear the collection list
      this.CreateSymbolsList(true);
      //--- Clear the market watch window snapshot
      this.CopySymbolsNames();
      //--- save the current hash some as the previous one
      this.m_hash_sum_prev=this.m_hash_sum;
      //--- save the current number of visible symbols as the previous one
      this.m_total_symbol_prev=this.m_total_symbols;
      return;
     }
   
//--- If the hash sum of symbols in the Market Watch window has changed
   if(this.m_hash_sum!=this.m_hash_sum_prev)
     {
      //--- Define the Market Watch window event
      this.m_delta_symbol=this.m_total_symbols-this.m_total_symbol_prev;
      ENUM_SYMBOL_EVENT event_id=
        (
         this.m_total_symbols>this.m_total_symbol_prev ? SYMBOL_EVENT_MW_ADD :
         this.m_total_symbols<this.m_total_symbol_prev ? SYMBOL_EVENT_MW_DEL :
         SYMBOL_EVENT_MW_SORT
        );
      //--- Adding a symbol to the Market Watch window
      if(event_id==SYMBOL_EVENT_MW_ADD)
        {
         string name="";
         //--- In the loop by all Market Watch window symbols
         int total=::SymbolsTotal(true), index=WRONG_VALUE;
         for(int i=0;i<total;i++)
           {
            //--- get the symbol name and check its "visibility". Skip it if invisible
            name=::SymbolName(i,true);
            if(!::SymbolInfoInteger(name,SYMBOL_VISIBLE))
               continue;
            //--- If there is no symbol in the collection symbol list yet
            if(!this.IsPresentSymbolInList(name))
              {
               //--- clear the collection list
               this.m_list_all_symbols.Clear();
               //--- recreate the collection list
               this.CreateSymbolsList(true);
               //--- create the symbol collection snapshot
               this.CopySymbolsNames();
               //--- get a new symbol index in the Market Watch window
               index=this.GetSymbolIndexByName(name);
               //--- If the "Adding a new symbol" event is successfully added to the event list 
               if(this.EventAdd(event_id,this.TickTime(),index,name))
                 {
                  //--- send the event to the chart:
                  //--- long value = event time in milliseconds, double value = symbol index, string value = added symbol name
                  ::EventChartCustom(this.m_chart_id,(ushort)event_id,this.TickTime(),index,name);
                 }
              }
           }
         //--- Save the new number of visible symbols in the market watch window
         this.m_total_symbols=this.SymbolsTotalVisible();
        }
      //--- Remove a symbol from the Market Watch window
      else if(event_id==SYMBOL_EVENT_MW_DEL)
        {
         //--- clear the collection list 
         this.m_list_all_symbols.Clear();
         //--- recreate the collection list
         this.CreateSymbolsList(true);
         //--- In a loop by the market watch window snapshot
         int total=this.m_list_names.Total();
         for(int i=0; i<total;i++)
           {
            //--- get a symbol name 
            string name=this.m_list_names.At(i);
            if(name==NULL)
               continue;
            //--- if no symbol with such a name exists in the collection symbol list
            if(!this.IsPresentSymbolInList(name))
              {
               //--- If the "Removing a symbol" event is successfully added to the event list
               if(this.EventAdd(event_id,this.TickTime(),WRONG_VALUE,name))
                 {
                  //--- send the event to the chart:
                  //--- long value = event tine in milliseconds, double value = -1 for an absent symbol, string value = a removed symbol name
                  ::EventChartCustom(this.m_chart_id,(ushort)event_id,this.TickTime(),WRONG_VALUE,name);
                 }
              }
           }
         //--- Recreate the market watch snapshot
         this.CopySymbolsNames();
         //--- Save the new number of visible symbols in the market watch window
         this.m_total_symbols=this.SymbolsTotalVisible();
        }
      //--- Sorting symbols in the Market Watch window
      else if(event_id==SYMBOL_EVENT_MW_SORT)
        {
         //--- clear the collection list 
         this.m_list_all_symbols.Clear();
         //--- set sorting of the collection list as sorting by index
         this.m_list_all_symbols.Sort(SORT_BY_SYMBOL_INDEX_MW);
         //--- recreate the collection list
         this.CreateSymbolsList(true);
         //--- get the current symbol index in the Market Watch window
         int index=this.GetSymbolIndexByName(Symbol());
         //--- send the event to the chart:
         //--- long value = event time in milliseconds, double value = current symbol index, string value = current symbol name
         ::EventChartCustom(this.m_chart_id,(ushort)event_id,this.TickTime(),index,::Symbol());
        }
      //--- save the current number of visible symbols as the previous one
      this.m_total_symbol_prev=this.m_total_symbols;
      //--- save the current hash some as the previous one
      this.m_hash_sum_prev=this.m_hash_sum;
     }
  }
//+------------------------------------------------------------------+

Para não descrever todas as ramificações no código do método, eu marquei o código na listagem de blocos e pus comentários detalhados em cada um dos blocos. Espero que tudo fique claro com uma análise independente. Se você tiver alguma dúvida, pode expressá-la nos comentários do artigo.

Ao trabalhar com a janela "Observação do Mercado" para rastrear os eventos que ocorrem nela, não é suficiente operar apenas com uma soma de hash. De fato, para descobrir o que aconteceu antes do evento, precisamos ter uma cópia da lista de símbolos na janela "Observação do Mercado" (molde da Observação do Mercado), e graças a esse molde sempre podemos saber, por exemplo, qual símbolo foi excluído. Sem um molde da janela "Observação do Mercado", não é possível conhecer o nome do símbolo excluído.

Método para criar um molde da janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Save names of used Market Watch symbols                          |
//+------------------------------------------------------------------+
void CSymbolsCollection::CopySymbolsNames(void)
  {
   this.m_list_names.Clear();
   int total=this.m_list_all_symbols.Total();
   for(int i=0;i<total;i++)
     {
      CSymbol *symbol=this.m_list_all_symbols.At(i);
      if(symbol==NULL)
         continue;
      this.m_list_names.Add(symbol.Name());
     }
  }
//+------------------------------------------------------------------+

Neste caso, limpamos a lista de nomes de símbolos, num ciclo através da lista de símbolos da coleção obtemos o próximo símbolo e o adicionamos à lista de nomes de símbolos.
No final do ciclo, teremos uma lista contendo os nomes de todos os símbolos na lista da coleção de símbolos.

Método que retorna um objeto-símbolo pelo nome:

//+------------------------------------------------------------------+
//| Return an object symbol from the list by a name                  |
//+------------------------------------------------------------------+
CSymbol *CSymbolsCollection::GetSymbolByName(const string name)
  {
   CArrayObj *list=this.GetList(SYMBOL_PROP_NAME,name,EQUAL);
   if(list==NULL || list.Total()==0)
      return NULL;
   CSymbol *symbol=list.At(0);
   return(symbol!=NULL ? symbol : NULL);
  }
//+------------------------------------------------------------------+

Para o método é transferido o nome do símbolo. Em seguida, usando o método para obter uma lista de objetos GetList() de acordo com a propriedade "Nome do símbolo" criamos uma nova lista, na qual deve haver um único objeto-símbolo, desde que o seu nome coincida com o nome passado para o método.
Obtemos o objeto-símbolo desta lista e o devolvemos com um resultado de pesquisa bem-sucedido ou NULL se não houver nenhum símbolo com o mesmo nome na lista de símbolos.

Método que retorna o índice do símbolo na lista-coleção de símbolos:

//+------------------------------------------------------------------+
//| Return the symbol object index from the list by a name           |
//+------------------------------------------------------------------+
int CSymbolsCollection::GetSymbolIndexByName(const string name)
  {
   int total=this.m_list_all_symbols.Total();
   for(int i=0;i<total;i++)
     {
      CSymbol *symbol=this.m_list_all_symbols.At(i);
      if(symbol==NULL)
         continue;
      if(symbol.Name()==name)
         return i;
     }
   return WRONG_VALUE;
  }
//+------------------------------------------------------------------+

Neste caso, para o método é transferido o nome do símbolo procurado. Em seguida, num ciclo para todos os símbolos que estão na lista de símbolos da coleção, obtemos o próximo objeto-símbolo da lista. Se o seu nome coincidir com o procurado, retornamos o índice do ciclo. Caso contrário, retornamos -1.

Método que retorna uma descrição do evento na janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Return the Market Watch window event description                 |
//+------------------------------------------------------------------+
string CSymbolsCollection::EventDescription(const ENUM_SYMBOL_EVENT event)
  {
   return
     (
      event==SYMBOL_EVENT_MW_ADD     -- TextByLanguage("В окно \"Обзор рынка\" добавлен символ","Added a symbol to the \"Market Watch\" window")                                     :
      event==SYMBOL_EVENT_MW_DEL     -- TextByLanguage("Из окна \"Обзор рынка\" удалён символ","From the \"Market Watch\" window was removed")                                       :
      event==SYMBOL_EVENT_MW_SORT    -- TextByLanguage("Изменено расположение символов в окне \"Обзор рынка\"","Changed the arrangement of symbols in the \"Market Watch\" window")  :
      EnumToString(event)
     );
  }
//+------------------------------------------------------------------+

Para o método é transferido o evento, e com base no tipo de evento transferido, é retornada sua descrição textual.

Método que retorna uma descrição do modo usado para trabalhar com os símbolos:

//+------------------------------------------------------------------+
//| Return a description of the mode of working with symbols         |
//+------------------------------------------------------------------+
string CSymbolsCollection::ModeSymbolsListDescription(void)
  {
   return
     (
      this.m_mode_list==SYMBOLS_MODE_CURRENT       ? TextByLanguage("Работа только с текущим символом","Work only with the current symbol")                                : 
      this.m_mode_list==SYMBOLS_MODE_DEFINES       ? TextByLanguage("Работа с предопределённым списком символов","Work with a predefined list of symbols")                 :
      this.m_mode_list==SYMBOLS_MODE_MARKET_WATCH  ? TextByLanguage("Работа с символами из окна \"Обзор рынка\"","Working with symbols from the \"Market Watch\" window")  :
      TextByLanguage("Работа с полным списком всех доступных символов","Work with the full list of all available symbols")
     );
  }
//+------------------------------------------------------------------+

Neste caso, é verificado o valor da variável m_mode_list e é retornada a descrição textual do modo de trabalho de acordo com o valor da variável em questão.

A criação da classe de eventos de símbolos está concluída.

Antes de começar a usar a classe de eventos de símbolos, lembramos que na classe de eventos da conta também podemos realizar o rastreamento de eventos — agora ela tem o objeto base CBaseObj, assim como a classe de conta agora também é baseada no CBaseObj, o que significa que ambos têm a capacidade usar a funcionalidade preparada para pesquisar eventos. Todos os próximos objetos que serão descendentes de CBaseObj também terão propriedades que permitem acompanhar os eventos destes objetos.

Aprimorando a classe de eventos da conta

Abrimos o arquivo de classe de conta Account.mqh e fazemos as alterações necessárias.
Substituímos a conexão do arquivo Object.mqh pela conexão BaseObj.mqh:

//+------------------------------------------------------------------+
//|                                                      Account.mqh |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                             https://mql5.com/pt/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://mql5.com/pt/users/artmedia70"
#property version   "1.00"
//+------------------------------------------------------------------+
//| Include files                                                    |
//+------------------------------------------------------------------+
#include "..\BaseObj.mqh"
#include "..\..\Services\DELib.mqh"
//+------------------------------------------------------------------+
//| Account class                                                    |
//+------------------------------------------------------------------+
class CAccount : public CBaseObj
  {
private:

Agora, em vez da classe CObject, fazemos com que CBaseObj seja a classe base.

Como agora temos a oportunidade de dar nome ao objeto herdado de CBaseObj, definiremos seu nome para o objeto-conta.
No final do construtor da classe CAccount inserimos uma linha definindo o nome do objeto-conta:

//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CAccount::CAccount(void)
  {
//--- Save integer properties
   this.m_long_prop[ACCOUNT_PROP_LOGIN]                              = ::AccountInfoInteger(ACCOUNT_LOGIN);
   this.m_long_prop[ACCOUNT_PROP_TRADE_MODE]                         = ::AccountInfoInteger(ACCOUNT_TRADE_MODE);
   this.m_long_prop[ACCOUNT_PROP_LEVERAGE]                           = ::AccountInfoInteger(ACCOUNT_LEVERAGE);
   this.m_long_prop[ACCOUNT_PROP_LIMIT_ORDERS]                       = ::AccountInfoInteger(ACCOUNT_LIMIT_ORDERS);
   this.m_long_prop[ACCOUNT_PROP_MARGIN_SO_MODE]                     = ::AccountInfoInteger(ACCOUNT_MARGIN_SO_MODE);
   this.m_long_prop[ACCOUNT_PROP_TRADE_ALLOWED]                      = ::AccountInfoInteger(ACCOUNT_TRADE_ALLOWED);
   this.m_long_prop[ACCOUNT_PROP_TRADE_EXPERT]                       = ::AccountInfoInteger(ACCOUNT_TRADE_EXPERT);
   this.m_long_prop[ACCOUNT_PROP_MARGIN_MODE]                        = #ifdef __MQL5__::AccountInfoInteger(ACCOUNT_MARGIN_MODE) #else ACCOUNT_MARGIN_MODE_RETAIL_HEDGING #endif ;
   this.m_long_prop[ACCOUNT_PROP_CURRENCY_DIGITS]                    = #ifdef __MQL5__::AccountInfoInteger(ACCOUNT_CURRENCY_DIGITS) #else 2 #endif ;
   this.m_long_prop[ACCOUNT_PROP_SERVER_TYPE]                        = (::TerminalInfoString(TERMINAL_NAME)=="MetaTrader 5" ? 5 : 4);
   
//--- Save real properties
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_BALANCE)]          = ::AccountInfoDouble(ACCOUNT_BALANCE);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_CREDIT)]           = ::AccountInfoDouble(ACCOUNT_CREDIT);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_PROFIT)]           = ::AccountInfoDouble(ACCOUNT_PROFIT);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_EQUITY)]           = ::AccountInfoDouble(ACCOUNT_EQUITY);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN)]           = ::AccountInfoDouble(ACCOUNT_MARGIN);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN_FREE)]      = ::AccountInfoDouble(ACCOUNT_MARGIN_FREE);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN_LEVEL)]     = ::AccountInfoDouble(ACCOUNT_MARGIN_LEVEL);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN_SO_CALL)]   = ::AccountInfoDouble(ACCOUNT_MARGIN_SO_CALL);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN_SO_SO)]     = ::AccountInfoDouble(ACCOUNT_MARGIN_SO_SO);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN_INITIAL)]   = ::AccountInfoDouble(ACCOUNT_MARGIN_INITIAL);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_MARGIN_MAINTENANCE)]=::AccountInfoDouble(ACCOUNT_MARGIN_MAINTENANCE);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_ASSETS)]           = ::AccountInfoDouble(ACCOUNT_ASSETS);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_LIABILITIES)]      = ::AccountInfoDouble(ACCOUNT_LIABILITIES);
   this.m_double_prop[this.IndexProp(ACCOUNT_PROP_COMMISSION_BLOCKED)]=::AccountInfoDouble(ACCOUNT_COMMISSION_BLOCKED);
   
//--- Save string properties
   this.m_string_prop[this.IndexProp(ACCOUNT_PROP_NAME)]             = ::AccountInfoString(ACCOUNT_NAME);
   this.m_string_prop[this.IndexProp(ACCOUNT_PROP_SERVER)]           = ::AccountInfoString(ACCOUNT_SERVER);
   this.m_string_prop[this.IndexProp(ACCOUNT_PROP_CURRENCY)]         = ::AccountInfoString(ACCOUNT_CURRENCY);
   this.m_string_prop[this.IndexProp(ACCOUNT_PROP_COMPANY)]          = ::AccountInfoString(ACCOUNT_COMPANY);

//--- Account object name
   this.m_name=TextByLanguage("Счёт ","Account ")+(string)this.Login()+": "+this.Name()+" ("+this.Company()+")";
  }
//+-------------------------------------------------------------------+

Como podemos ver, o nome do objeto consistirá no texto "Conta", número da conta, nome do cliente e o nome da empresa que atende a conta.
Por exemplo, ao conectar-se a uma das contas no MetaQuotes-Demo com o meu nome, o nome do objeto da conta ficará assim: "Account 8550475: Artyom Trishkin (MetaQuotes Software Corp.)"

No método de exibição do nome abreviado da conta escrevemos o valor da variável names (anteriormente, era definido da mesma maneira que agora definimos o nome do objeto-conta):

//+------------------------------------------------------------------+
//| Display a short account description in the journal               |
//+------------------------------------------------------------------+
void CAccount::PrintShort(void)
  {
   string mode=(this.MarginMode()==ACCOUNT_MARGIN_MODE_RETAIL_HEDGING ? ", Hedge" : this.MarginMode()==ACCOUNT_MARGIN_MODE_EXCHANGE ? ", Exhange" : "");
   string names=this.m_name+" ";
   string values=::DoubleToString(this.Balance(),(int)this.CurrencyDigits())+" "+this.Currency()+", 1:"+(string)+this.Leverage()+mode+", "+this.TradeModeDescription()+" "+this.ServerTypeDescription();
   ::Print(names,values);
  }
//+------------------------------------------------------------------+

Essas são todas as melhorias na classe CAccount.

Agora vamos aprimorar a classe de coleção de contas. Abrimos arquivo AccountsCollection.mqh e escrevemos as alterações necessárias.
Tornamos a classe CBaseObj um objeto base da classe de coleção de contas:

//+------------------------------------------------------------------+
//| Account collection                                               |
//+------------------------------------------------------------------+
class CAccountsCollection : public CBaseObj
  {
private:

Como a classe agora é herdada do objeto base, no qual já está registrada a funcionalidade para rastrear os eventos do objeto, removeremos as variáveis e os métodos que foram duplicados na classe de coleção de contas.
Na estrutura de dados da conta excluímos o campo de soma de hash:

   struct MqlDataAccount
     {
      double         hash_sum;               // Account data hash sum
      //--- Account integer properties
      long           login;                  // ACCOUNT_LOGIN (Account number)
      long           leverage;               // ACCOUNT_LEVERAGE (Leverage)
      int            limit_orders;           // ACCOUNT_LIMIT_ORDERS (Maximum allowed number of active pending orders)
      bool           trade_allowed;          // ACCOUNT_TRADE_ALLOWED (Permission to trade for the current account from the server side)
      bool           trade_expert;           // ACCOUNT_TRADE_EXPERT (Permission to trade for an EA from the server side)
      //--- Account real properties
      double         balance;                // ACCOUNT_BALANCE (Account balance in a deposit currency)
      double         credit;                 // ACCOUNT_CREDIT (Credit in a deposit currency)
      double         profit;                 // ACCOUNT_PROFIT (Current profit on an account in the account currency)
      double         equity;                 // ACCOUNT_EQUITY (Equity on an account in the deposit currency)
      double         margin;                 // ACCOUNT_MARGIN (Reserved margin on an account in a deposit currency)
      double         margin_free;            // ACCOUNT_MARGIN_FREE (Free funds available for opening a position in a deposit currency)
      double         margin_level;           // ACCOUNT_MARGIN_LEVEL (Margin level on an account in %)
      double         margin_so_call;         // ACCOUNT_MARGIN_SO_CALL (MarginCall)
      double         margin_so_so;           // ACCOUNT_MARGIN_SO_SO (StopOut)
      double         margin_initial;         // ACCOUNT_MARGIN_INITIAL (Funds reserved on an account to ensure a guarantee amount for all pending orders)
      double         margin_maintenance;     // ACCOUNT_MARGIN_MAINTENANCE (Funds reserved on an account to ensure a minimum amount for all open positions)
      double         assets;                 // ACCOUNT_ASSETS (Current assets on an account)
      double         liabilities;            // ACCOUNT_LIABILITIES (Current liabilities on an account)
      double         comission_blocked;      // ACCOUNT_COMMISSION_BLOCKED (Current sum of blocked commissions on an account)
     };

Removemos as variáveis-membros privados da classe:

   MqlTick           m_tick;                             // Tick structure
   string            m_symbol;                           // Current symbol
   long              m_chart_id;                         // Control program chart ID
   CListObj          m_list_accounts;                    // Account object list
   CArrayInt         m_list_changes;                     // Account change list
   string            m_folder_name;                      // Name of a folder account objects are stored
   int               m_index_current;                    // Index of an account object featuring the current account data
//--- Tracking account changes
   bool              m_is_account_event;                 // Account data event flag
   int               m_change_code;                      // Account change code

Renomeamos o método SetChangeCode() para SetEventCode(), para que os nomes dos mesmos métodos sejam os mesmos em classes diferentes.
Tornamos o método SetTypeEvent() virtual, pois ele já está declarado na classe CBaseObj e deve ser implementado nos herdeiros.
Na classe removemos o método IsPresentEventFlag(), uma vez que ele já está implementado em CBaseObj.

Na seção pública da classe, também reduzimos ligeiramente os métodos duplicados.
Removemos os métodos GetEventCode(), GetListChanges() e SetChartID(), e fazemos com que o método ENUM_ACCOUNT_EVENT GetEvent(const int shift=WRONG_VALUE) fique assim:

ENUM_ACCOUNT_EVENT GetEventID(const int shift=WRONG_VALUE,const bool check_out=true);

Consideramos imediatamente sua implementação fora do corpo da classe:

//+------------------------------------------------------------------+
//| Return the account event by its number in the list               |
//+------------------------------------------------------------------+
ENUM_ACCOUNT_EVENT CAccountsCollection::GetEventID(const int shift=WRONG_VALUE,const bool check_out=true)
  {
   CEventBaseObj *event=this.GetEvent(shift,check_out);
   if(event==NULL)
      return ACCOUNT_EVENT_NO_EVENT;
   return (ENUM_ACCOUNT_EVENT)event.ID();
  }
//+------------------------------------------------------------------+

Para o método é passado o índice do evento desejado (-1 para selecionar o último) e o sinalizador que controla a saída do índice além do tamanho da lista de eventos.
Obtemos o objeto do even´com a ajuda do método do objeto base CBaseObj GetEvent(), que abordamos no início do artigo. Se não houver eventos, retornamos "Nenhum evento", caso contrário, retornamos o identificador do evento.

No construtor da classe, na sua lista de inicialização, removemos a inicialização de todos os parâmetros exceto a definição de símbolo, e definimos o nome da subpasta para armazenar arquivos de objetos-conta:

//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CAccountsCollection::CAccountsCollection(void) : m_symbol(::Symbol())
  {
   this.m_list_accounts.Clear();
   this.m_list_accounts.Sort(SORT_BY_ACCOUNT_LOGIN);
   this.m_list_accounts.Type(COLLECTION_ACCOUNT_ID);
   ::ZeroMemory(this.m_struct_prev_account);
   ::ZeroMemory(this.m_tick);
   this.InitChangesParams();
   this.InitControlsParams();
//--- Create the folder for storing account files
   this.SetSubFolderName("Accounts");
   ::ResetLastError();
   if(!::FolderCreate(this.m_folder_name,FILE_COMMON))
      ::Print(DFUN,TextByLanguage("Не удалось создать папку хранения файлов. Ошибка ","Could not create file storage folder. Error "),::GetLastError());
//--- Create the current account object and add it to the list
   CAccount* account=new CAccount();
   if(account!=NULL)
     {
      if(!this.AddToList(account))
        {
         ::Print(DFUN_ERR_LINE,TextByLanguage("Ошибка. Не удалось добавить текущий объект-аккаунт в список-коллекцию.","Error. Failed to add current account object to collection list."));
         delete account;
        }
      else
         account.PrintShort();
     }
   else
      ::Print(DFUN,TextByLanguage("Ошибка. Не удалось создать объект-аккаунт с данными текущего счёта.","Error. Failed to create an account object with current account data."));

//--- Download account objects from the files to the collection
   this.LoadObjects();
//--- Save the current account index
   this.m_index_current=this.Index();
  }
//+------------------------------------------------------------------+

Tornamos virtual o método de atualização de dados da conta Refresh(), uma vez que ele é declarado na classe CBaseObj e é implementado em seus descendentes.

Existem algumas alterações na implementação do método:

//+------------------------------------------------------------------+
//| Update the current account data                                  |
//+------------------------------------------------------------------+
void CAccountsCollection::Refresh(void)
  {
   ::ResetLastError();
   if(!::SymbolInfoTick(::Symbol(),this.m_tick))
     {
      this.m_global_error=::GetLastError();
      return;
     }
   if(this.m_index_current==WRONG_VALUE)
      return;
   CAccount* account=this.m_list_accounts.At(this.m_index_current);
   if(account==NULL)
      return;
//--- Prepare event data
   this.m_is_event=false;
   ::ZeroMemory(this.m_struct_curr_account);
   this.m_hash_sum=0;
   this.SetAccountsParams(account);

//--- First launch
   if(!this.m_struct_prev_account.login)
     {
      this.m_struct_prev_account=this.m_struct_curr_account;
      this.m_hash_sum_prev=this.m_hash_sum;
      return;
     }
//--- If the account hash sum changed
   if(this.m_hash_sum!=this.m_hash_sum_prev)
     {
      this.m_list_events.Clear();
      this.m_event_code=this.SetEventCode();
      this.SetTypeEvent();
      int total=this.m_list_events.Total();
      if(total>0)
        {
         this.m_is_event=true;
         for(int i=0;i<total;i++)
           {
            CEventBaseObj *event=this.GetEvent(i,false);
            if(event==NULL)
               continue;
            ENUM_ACCOUNT_EVENT event_id=(ENUM_ACCOUNT_EVENT)event.ID();
            if(event_id==ACCOUNT_EVENT_NO_EVENT)
               continue;
            long lparam=event.LParam();
            double dparam=event.DParam();
            string sparam=event.SParam();
            ::EventChartCustom(this.m_chart_id,(ushort)event_id,lparam,dparam,sparam);
           }
        }
      this.m_hash_sum_prev=this.m_hash_sum;
     }
  }
//+------------------------------------------------------------------+

Consideramos apenas as alterações feitas.
Primeiro, os dados de cotação do símbolo (para determinar o tempo em milissegundos), e se não for possível obtê-los, saímos do método.

Redefinimos o sinalizador do evento da conta e o valor da atual soma de hash. Na primeira inicialização, salvamos o valor da atual soma de hash como a anterior.

Ao alterar as somas de hash, limpamos a lista de eventos da conta, e realizamos exatamente as mesmas ações para obter eventos da lista de eventos da conta que fizemos quando recebemos a lista de eventos de símbolos, e que foram discutidos aqui acima.

Agora, para qualquer objeto herdado de CBaseObj, as ações para receber seus eventos serão idênticas. Portanto, é melhor familiarizar-se novamente com o recebimento, que examinamos neste artigo, para que nos próximos artigos tudo fique claro e não ter de abordar mais uma vez a as ações executadas para obter uma lista de eventos de objetos.

No método de armazenamento de propriedades da conta no objeto-conta e na estrutura de dados da conta, substituímos o acesso ao campo da estrutura de soma de hash pela variável de classe CBaseObj de soma de hash, e armazenamos o nome do objeto:

//+------------------------------------------------------------------+
//| Write the current account data to the account object properties  |
//+------------------------------------------------------------------+
void CAccountsCollection::SetAccountsParams(CAccount *account)
  {
   if(account==NULL)
      return;
//--- Name
   this.m_name=account.GetName();
//--- Account number
   this.m_struct_curr_account.login=account.Login();
//--- Leverage
   account.SetProperty(ACCOUNT_PROP_LEVERAGE,::AccountInfoInteger(ACCOUNT_LEVERAGE));
   this.m_struct_curr_account.leverage=account.Leverage();
   this.m_hash_sum+=(double)this.m_struct_curr_account.leverage;
//--- Maximum allowed number of active pending orders
   account.SetProperty(ACCOUNT_PROP_LIMIT_ORDERS,::AccountInfoInteger(ACCOUNT_LIMIT_ORDERS));
   this.m_struct_curr_account.limit_orders=(int)account.LimitOrders();
   this.m_hash_sum+=(double)this.m_struct_curr_account.limit_orders;
//--- Permission to trade for the current account from the server side
   account.SetProperty(ACCOUNT_PROP_TRADE_ALLOWED,::AccountInfoInteger(ACCOUNT_TRADE_ALLOWED));
   this.m_struct_curr_account.trade_allowed=account.TradeAllowed();
   this.m_hash_sum+=(double)this.m_struct_curr_account.trade_allowed;
//--- Permission to trade for an EA from the server side
   account.SetProperty(ACCOUNT_PROP_TRADE_EXPERT,::AccountInfoInteger(ACCOUNT_TRADE_EXPERT));
   this.m_struct_curr_account.trade_expert=account.TradeExpert();
   this.m_hash_sum+=(double)this.m_struct_curr_account.trade_expert;
//--- Account balance in a deposit currency
   account.SetProperty(ACCOUNT_PROP_BALANCE,::AccountInfoDouble(ACCOUNT_BALANCE));
   this.m_struct_curr_account.balance=account.Balance();
   this.m_hash_sum+=(double)this.m_struct_curr_account.balance;
//--- Credit in a deposit currency
   account.SetProperty(ACCOUNT_PROP_CREDIT,::AccountInfoDouble(ACCOUNT_CREDIT));
   this.m_struct_curr_account.credit=account.Credit();
   this.m_hash_sum+=(double)this.m_struct_curr_account.credit;
//--- Current profit on an account in the account currency
   account.SetProperty(ACCOUNT_PROP_PROFIT,::AccountInfoDouble(ACCOUNT_PROFIT));
   this.m_struct_curr_account.profit=account.Profit();
   this.m_hash_sum+=(double)this.m_struct_curr_account.profit;
//--- Equity on an account in the deposit currency
   account.SetProperty(ACCOUNT_PROP_EQUITY,::AccountInfoDouble(ACCOUNT_EQUITY));
   this.m_struct_curr_account.equity=account.Equity();
   this.m_hash_sum+=(double)this.m_struct_curr_account.equity;
//--- Reserved margin on an account in the deposit currency
   account.SetProperty(ACCOUNT_PROP_MARGIN,::AccountInfoDouble(ACCOUNT_MARGIN));
   this.m_struct_curr_account.margin=account.Margin();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin;
//--- Free funds available for opening a position on an account in the deposit currency
   account.SetProperty(ACCOUNT_PROP_MARGIN_FREE,::AccountInfoDouble(ACCOUNT_MARGIN_FREE));
   this.m_struct_curr_account.margin_free=account.MarginFree();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin_free;
//--- Margin level on an account in %
   account.SetProperty(ACCOUNT_PROP_MARGIN_LEVEL,::AccountInfoDouble(ACCOUNT_MARGIN_LEVEL));
   this.m_struct_curr_account.margin_level=account.MarginLevel();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin_level;
//--- Margin Call level
   account.SetProperty(ACCOUNT_PROP_MARGIN_SO_CALL,::AccountInfoDouble(ACCOUNT_MARGIN_SO_CALL));
   this.m_struct_curr_account.margin_so_call=account.MarginSOCall();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin_so_call;
//--- Stop Out level
   account.SetProperty(ACCOUNT_PROP_MARGIN_SO_SO,::AccountInfoDouble(ACCOUNT_MARGIN_SO_SO));
   this.m_struct_curr_account.margin_so_so=account.MarginSOSO();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin_so_so;
//--- Funds reserved on an account to ensure a guarantee amount for all pending orders
   account.SetProperty(ACCOUNT_PROP_MARGIN_INITIAL,::AccountInfoDouble(ACCOUNT_MARGIN_INITIAL));
   this.m_struct_curr_account.margin_initial=account.MarginInitial();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin_initial;
//--- Funds reserved on an account to ensure a minimum amount for all open positions
   account.SetProperty(ACCOUNT_PROP_MARGIN_MAINTENANCE,::AccountInfoDouble(ACCOUNT_MARGIN_MAINTENANCE));
   this.m_struct_curr_account.margin_maintenance=account.MarginMaintenance();
   this.m_hash_sum+=(double)this.m_struct_curr_account.margin_maintenance;
//--- Current assets on an account
   account.SetProperty(ACCOUNT_PROP_ASSETS,::AccountInfoDouble(ACCOUNT_ASSETS));
   this.m_struct_curr_account.assets=account.Assets();
   this.m_hash_sum+=(double)this.m_struct_curr_account.assets;
//--- Current liabilities on an account
   account.SetProperty(ACCOUNT_PROP_LIABILITIES,::AccountInfoDouble(ACCOUNT_LIABILITIES));
   this.m_struct_curr_account.liabilities=account.Liabilities();
   this.m_hash_sum+=(double)this.m_struct_curr_account.liabilities;
//--- Current sum of blocked commissions on an account
   account.SetProperty(ACCOUNT_PROP_COMMISSION_BLOCKED,::AccountInfoDouble(ACCOUNT_COMMISSION_BLOCKED));
   this.m_struct_curr_account.comission_blocked=account.ComissionBlocked();
   this.m_hash_sum+=(double)this.m_struct_curr_account.comission_blocked;
  }
//+------------------------------------------------------------------+

Também foi modificado o método SetTypeEvent() da classe de coleção de contas, pois agora era possível definir os eventos de qualquer objeto. O método é grande, mas todas as ações para determinar os tipos de eventos da conta são do mesmo tipo, e já discutimos isso aqui ao analisar como definir tipos de eventos de símbolos. Portanto, darei apenas um exemplo de como determinar o evento de permissão de negociação na conta. Adicionalmente, uma listagem completa do método está disponível nos arquivos anexados ao artigo:

//+------------------------------------------------------------------+
//| Set the account object event type                                |
//+------------------------------------------------------------------+
void CAccountsCollection::SetTypeEvent(void)
  {
   this.InitChangesParams();
   ENUM_ACCOUNT_EVENT event_id=ACCOUNT_EVENT_NO_EVENT;
//--- Changing permission to trade for the account
   if(this.IsPresentEventFlag(ACCOUNT_EVENT_FLAG_TRADE_ALLOWED))
     {
      if(!this.m_struct_curr_account.trade_allowed)
        {
         this.m_is_change_trade_allowed_off=true;
         event_id=ACCOUNT_EVENT_TRADE_ALLOWED_OFF;
         if(this.EventAdd(event_id,this.TickTime(),this.m_is_change_trade_allowed_off,this.m_name))
            this.m_struct_prev_account.trade_allowed=this.m_struct_curr_account.trade_allowed;
        }
      else
        {
         this.m_is_change_trade_allowed_on=true;
         event_id=ACCOUNT_EVENT_TRADE_ALLOWED_ON;
         if(this.EventAdd(event_id,this.TickTime(),this.m_is_change_trade_allowed_on,this.m_name))
            this.m_struct_prev_account.trade_allowed=this.m_struct_curr_account.trade_allowed;
        }
     }
//--- Changing permission for auto trading for the account

Com isso, as alterações e o refinamento da classe de coleção de contas são concluídas, e podemos começar a trabalhar com classes atualizadas de eventos de símbolos e de conta.

Como lembramos, todo gerenciamento começa com a classe CEngine e todos os dados são enviados para ele. Não há exceções para as classes de eventos de símbolo e de conta.

Começando a trabalhar com uma classe de eventos de símbolos e com uma classe de conta atualizada

Abrimos o arquivo Engine.mqh e fazemos as alterações necessárias.

Na seção privada da classe, declaramos o sinalizador do evento do símbolo e o valor do último evento no símbolo:

//+------------------------------------------------------------------+
//| Library basis class                                              |
//+------------------------------------------------------------------+
class CEngine : public CObject
  {
private:
   CHistoryCollection   m_history;                       // Collection of historical orders and deals
   CMarketCollection    m_market;                        // Collection of market orders and deals
   CEventsCollection    m_events;                        // Event collection
   CAccountsCollection  m_accounts;                      // Account collection
   CSymbolsCollection   m_symbols;                       // Symbol collection
   CArrayObj            m_list_counters;                 // List of timer counters
   int                  m_global_error;                  // Global error code
   bool                 m_first_start;                   // First launch flag
   bool                 m_is_hedge;                      // Hedge account flag
   bool                 m_is_tester;                     // Flag of working in the tester
   bool                 m_is_market_trade_event;         // Account trading event flag
   bool                 m_is_history_trade_event;        // Account history trading event flag
   bool                 m_is_account_event;              // Account change event flag
   bool                 m_is_symbol_event;               // Symbol change event flag
   ENUM_TRADE_EVENT     m_last_trade_event;              // Last account trading event
   ENUM_ACCOUNT_EVENT   m_last_account_event;            // Last event in the account properties
   ENUM_SYMBOL_EVENT    m_last_symbol_event;             // Last event in the symbol properties
//--- Return the counter index by id

Na seção pública da classe, declaramos o método que retorna uma descrição do último evento de negociação:

//--- Return the list of historical (1) orders, (2) removed pending orders, (3) deals,
//--- (4) all market orders of a position by its ID, (5) description of the last trading event
   CArrayObj           *GetListHistoryOrders(void);
   CArrayObj           *GetListHistoryPendings(void);
   CArrayObj           *GetListDeals(void);
   CArrayObj           *GetListAllOrdersByPosID(const ulong position_id);
   string               GetLastTradeEventDescription(void);

E declaramos os novos métodos necessários para trabalhar com eventos de símbolos, também alteramos o método que retorna o sinalizador de evento da conta:

//--- Return the list of (1) used symbols, (2) symbol events, (3) the last symbol change event
//--- (4) the current symbol, (5) symbol event description, (6) Market Watch event description
   CArrayObj           *GetListAllUsedSymbols(void)                     { return this.m_symbols.GetList();                    }
   CArrayObj           *GetListSymbolsEvents(void)                      { return this.m_symbols.GetListEvents();              }
   ENUM_SYMBOL_EVENT    GetLastSymbolsEvent()                           { return this.m_symbols.GetLastEvent();               }
   CSymbol             *GetSymbolCurrent(void);
   string               GetSymbolEventDescription(ENUM_SYMBOL_EVENT event);
   string               GetMWEventDescription(ENUM_SYMBOL_EVENT event)  { return this.m_symbols.EventDescription(event);      }
   string               ModeSymbolsListDescription(void)                { return this.m_symbols.ModeSymbolsListDescription(); }
   
//--- Return the list of order, deal and position events
   CArrayObj           *GetListAllOrdersEvents(void)                    { return this.m_events.GetList();                     }
//--- Reset the last trading event
   void                 ResetLastTradeEvent(void)                       { this.m_events.ResetLastTradeEvent(); }
//--- Return the (1) last trading event, (2) the last event in the account properties, (3) hedging account flag, (4) flag of working in the tester
   ENUM_TRADE_EVENT     LastTradeEvent(void)                      const { return this.m_last_trade_event;                     }
   ENUM_ACCOUNT_EVENT   LastAccountEvent(void)                    const { return this.m_last_account_event;                   }
   ENUM_SYMBOL_EVENT    LastSymbolsEvent(void)                    const { return this.m_last_symbol_event;                    }
//--- Return the (1) hedge account, (2) working in the tester, (3) account event and (4) symbol event flag
   bool                 IsHedge(void)                             const { return this.m_is_hedge;                             }
   bool                 IsTester(void)                            const { return this.m_is_tester;                            }
   bool                 IsAccountsEvent(void)                     const { return this.m_accounts.IsEvent();                   }
   bool                 IsSymbolsEvent(void)                      const { return this.m_symbols.IsEvent();                    }
//--- Return the (1) symbol object by name, as well as the code of the last event of (2) an account and (3) a symbol
   CSymbol             *GetSymbolObjByName(const string name)           { return this.m_symbols.GetSymbolByName(name);        }
   int                  GetAccountEventsCode(void)                const { return this.m_accounts.GetEventCode();              }
   int                  GetSymbolsEventsCode(void)                const { return this.m_symbols.GetLastEventsCode();          }
//--- Return the number of (1) symbols, (2) events in the symbol collection
   int                  GetSymbolsCollectionTotal(void)           const { return this.m_symbols.GetSymbolsCollectionTotal();  }
   int                  GetSymbolsCollectionEventsTotal(void)     const { return this.m_symbols.GetEventsTotal();             }

No construtor da classe, em sua lista de inicialização, adicionamos a inicialização do último evento à coleção de símbolos:

//+------------------------------------------------------------------+
//| CEngine constructor                                              |
//+------------------------------------------------------------------+
CEngine::CEngine() : m_first_start(true),
                     m_last_trade_event(TRADE_EVENT_NO_EVENT),
                     m_last_account_event(ACCOUNT_EVENT_NO_EVENT),
                     m_last_symbol_event(SYMBOL_EVENT_NO_EVENT),
                     m_global_error(ERR_SUCCESS)
  {
   this.m_is_hedge=#ifdef __MQL4__ true #else bool(::AccountInfoInteger(ACCOUNT_MARGIN_MODE)==ACCOUNT_MARGIN_MODE_RETAIL_HEDGING) #endif;
   this.m_is_tester=::MQLInfoInteger(MQL_TESTER);
   
   this.m_list_counters.Sort();
   this.m_list_counters.Clear();
   this.CreateCounter(COLLECTION_ORD_COUNTER_ID,COLLECTION_ORD_COUNTER_STEP,COLLECTION_ORD_PAUSE);
   this.CreateCounter(COLLECTION_ACC_COUNTER_ID,COLLECTION_ACC_COUNTER_STEP,COLLECTION_ACC_PAUSE);
   
   this.CreateCounter(COLLECTION_SYM_COUNTER_ID1,COLLECTION_SYM_COUNTER_STEP1,COLLECTION_SYM_PAUSE1);
   this.CreateCounter(COLLECTION_SYM_COUNTER_ID2,COLLECTION_SYM_COUNTER_STEP2,COLLECTION_SYM_PAUSE2);
   
   ::ResetLastError();
   #ifdef __MQL5__
      if(!::EventSetMillisecondTimer(TIMER_FREQUENCY))
        {
         ::Print(DFUN_ERR_LINE,"Не удалось создать таймер. Ошибка: ","Could not create timer. Error: ",(string)::GetLastError());
         this.m_global_error=::GetLastError();
        }
   //---__MQL4__
   #else 
      if(!this.IsTester() && !::EventSetMillisecondTimer(TIMER_FREQUENCY))
        {
         ::Print(DFUN_ERR_LINE,"Не удалось создать таймер. Ошибка: ","Could not create timer. Error: ",(string)::GetLastError());
         this.m_global_error=::GetLastError();
        }
   #endif 
  }
//+------------------------------------------------------------------+

No manipulador do temporizador da classe, fazemos correções nos blocos de processamento timer1 e timer2 das coleções de símbolos:

//+------------------------------------------------------------------+
//| CEngine timer                                                    |
//+------------------------------------------------------------------+
void CEngine::OnTimer(void)
  {
//--- Timer of the collections of historical orders and deals, as well as of market orders and positions
   int index=this.CounterIndex(COLLECTION_ORD_COUNTER_ID);
   if(index>WRONG_VALUE)
     {
      CTimerCounter* counter=this.m_list_counters.At(index);
      if(counter!=NULL)
        {
         //--- If this is not a tester
         if(!this.IsTester())
           {
            //--- If unpaused, work with the order, deal and position collections events
            if(counter.IsTimeDone())
               this.TradeEventsControl();
           }
         //--- If this is a tester, work with collection events by tick
         else
            this.TradeEventsControl();
        }
     }
//--- Account collection timer
   index=this.CounterIndex(COLLECTION_ACC_COUNTER_ID);
   if(index>WRONG_VALUE)
     {
      CTimerCounter* counter=this.m_list_counters.At(index);
      if(counter!=NULL)
        {
         //--- If this is not a tester
         if(!this.IsTester())
           {
            //--- If unpaused, work with the account collection events
            if(counter.IsTimeDone())
               this.AccountEventsControl();
           }
         //--- If this is a tester, work with collection events by tick
         else
            this.AccountEventsControl();
        }
     }
     
//--- Timer 1 of the symbol collection (updating symbol quote data in the collection)
   index=this.CounterIndex(COLLECTION_SYM_COUNTER_ID1);
   if(index>WRONG_VALUE)
     {
      CTimerCounter* counter=this.m_list_counters.At(index);
      if(counter!=NULL)
        {
         //--- If this is not a tester
         if(!this.IsTester())
           {
            //--- If the pause is over, update quote data of all symbols in the collection
            if(counter.IsTimeDone())
               this.m_symbols.RefreshRates();
           }
         //--- In case of a tester, update quote data of all collection symbols by tick
         else
            this.m_symbols.RefreshRates();
        }
     }
//--- Timer 2 of the symbol collection (updating all data of all symbols in the collection and tracking symbl and symbol search events in the market watch window)
   index=this.CounterIndex(COLLECTION_SYM_COUNTER_ID2);
   if(index>WRONG_VALUE)
     {
      CTimerCounter* counter=this.m_list_counters.At(index);
      if(counter!=NULL)
        {
         //--- If this is not a tester
         if(!this.IsTester())
           {
            //--- If the pause is over
            if(counter.IsTimeDone())
              {
               //--- update data and work with events of all symbols in the collection
               this.SymbolEventsControl();
               //--- When working with the market watch list, check the market watch window events
               if(this.m_symbols.ModeSymbolsList()==SYMBOLS_MODE_MARKET_WATCH)
                  this.MarketWatchEventsControl();
              }
           }
         //--- If this is a tester, work with events of all symbols in the collection by tick
         else
            this.SymbolEventsControl();
        }
     }
  }
//+------------------------------------------------------------------+

Neste caso, na terminação do contador do temporizador1, só precisamos atualizar os dados da cotação de todos os símbolos da coleção, portanto chamamos o método RefreshRates() da coleção de símbolos.
Na terminação do contador do temporizador2, precisamos fazer uma atualização completa de todos os símbolos na coleção de símbolos e rastrear os eventos que ocorreram nos símbolos da coleção e na lista de símbolos na janela "Observação do Mercado". por isso, chamamos os métodos da classe CEngine SymbolEventsControl() e somente quando não estiver trabalhando no testador MarketWatchEventsControl().

Implementação do método de trabalho com eventos de coleção de símbolos:

//+------------------------------------------------------------------+
//| Working with symbol collection events                            |
//+------------------------------------------------------------------+
void CEngine::SymbolEventsControl(void)
  {
   this.m_symbols.SymbolsEventsControl();
   this.m_is_symbol_event=this.m_symbols.IsEvent();
//--- If there are changes in symbol properties
   if(this.m_is_symbol_event)
     {
      //--- Get the last event of the symbol property change
      this.m_last_symbol_event=this.m_symbols.GetLastEvent();
     }
  }
//+------------------------------------------------------------------+

Neste caso, chamamos o método de coleção de símbolos SymbolsEventsControl()discutido neste artigo acima ao falar sobre a classe de eventos de coleção de símbolos. Depois que esse método funcionar, será gerado um sinalizador de evento na classe de coleção de símbolos, desde que um evento tenha sido registrado em qualquer um dos símbolos da coleção e o estado desse sinalizador seja registrado usando o método IsEvent() da classe de objeto base CBaseObj na sinalizador-variável do evento da coleção de símbolos m_is_symbol_event cujo valor pode ser rastreado no programa de chamada. Se um evento foi registrado na coleção de símbolosescrevemos o último evento na variável m_last_symbol_event cujo valor também pode ser rastreado no programa de chamada.

Implementação do método para trabalhar com eventos da janela "Observação do Mercado":

//+------------------------------------------------------------------+
//| Working with symbol list events in the market watch window       |
//+------------------------------------------------------------------+
void CEngine::MarketWatchEventsControl(void)
  {
   if(this.IsTester())
      return;
   this.m_symbols.MarketWatchEventsControl();
  }
//+------------------------------------------------------------------+

Neste caso, se é o testador , saímos, caso contrário, chamamos o método MarketWatchEventsControl() da classe de coleção de símbolos para manipular os eventos da janela "Observação do Mercado", mencionada acima ao discutir o rastreamento de eventos para a classe de coleção de símbolos.

Implementação do método que retorna uma descrição do último evento de negociação:

//+------------------------------------------------------------------+
//| Return the description of the last trading event                 |
//+------------------------------------------------------------------+
string CEngine::GetLastTradeEventDescription(void)
  {
   CArrayObj *list=this.m_events.GetList();
   if(list!=NULL)
     {
      if(list.Total()==0)
         return TextByLanguage("С момента последнего запуска ЕА торговых событий не было","There have been no trade events since the last launch of EA");
      CEvent *event=list.At(list.Total()-1);
      if(event!=NULL)
         return event.TypeEventDescription();
     }
   return DFUN_ERR_LINE+TextByLanguage("Не удалось получить описание последнего торгового события","Failed to get the description of the last trading event");
  }
//+------------------------------------------------------------------+

Neste caso, obtemos a lista completa de eventos de negociação na conta. Se a lista for recebida, mas seu tamanho for zero, retornamos mensagem de que ainda não houve eventos de negociação, caso contrário, obtemos o último evento da lista e retornamos sua descrição. Caso contrário, retornamos uma mensagem sobre não ter recebido o evento de negociação com sucesso.

Método que retorna uma descrição do último evento na coleção de símbolos:

//+------------------------------------------------------------------+
//| Return the symbol event description                              |
//+------------------------------------------------------------------+
string CEngine::GetSymbolEventDescription(ENUM_SYMBOL_EVENT event)
  {
   CArrayObj *list=this.m_symbols.GetList();
   if(list!=NULL)
     {
      if(list.Total()==0)
         return TextByLanguage("С момента последнего запуска ЕА не было никаких событий символов","There have been no events of symbols since the last launch of EA");
      CSymbol *symbol=list.At(list.Total()-1);
      if(symbol!=NULL)
         return symbol.EventDescription(event);
     }
   return DFUN_ERR_LINE+TextByLanguage("Не удалось получить описание события символа","Failed to get symbol's event description");
  }
//+------------------------------------------------------------------+

O método funciona de forma idêntica ao método para retornar a descrição do último evento de negociação considerado agora.

O aprimoramento da classe CEngine está concluído e estamos prontos para testar eventos de símbolos, bem como a classe de conta atualizada e eventos de conta.

Algumas alterações foram introduzidas adicionalmente às classes que não foram abordadas no artigo, uma vez que, por exemplo, são apenas alterações nos nomes de alguns métodos, para que os mesmos métodos de classes diferentes tenham os mesmos nomes. Essas pequenas melhorias não precisam ser expressas no código da biblioteca que está em constante evolução e sempre podem ser vistas nos arquivos anexados aos artigos.

Teste de eventos de símbolos e de contas

Para testar, usamos o EA de tesde do último artigo, salvamo-lo com o nome \MQL5\Experts\TestDoEasy\ Part16\TestDoEasyPart16.mq5 e fazemos as alterações necessárias.

À lista de variáveis globais adcionamos uma variável para armazenar o modo usado para trabalhar com listas de símbolo:

//--- global variables
CEngine        engine;
#ifdef __MQL5__
CTrade         trade;
#endif 
SDataButt      butt_data[TOTAL_BUTT];
string         prefix;
double         lot;
double         withdrawal=(InpWithdrawal<0.1 ? 0.1 : InpWithdrawal);
ulong          magic_number;
uint           stoploss;
uint           takeprofit;
uint           distance_pending;
uint           distance_stoplimit;
uint           slippage;
bool           trailing_on;
double         trailing_stop;
double         trailing_step;
uint           trailing_start;
uint           stoploss_to_modify;
uint           takeprofit_to_modify;
int            used_symbols_mode;
string         used_symbols;
string         array_used_symbols[];

Como ao escolher o modo "Trabalhar com uma lista completa de símbolos no servidor", a primeira inicialização pode ser bastante longa, pois a coleção de símbolos precisa coletar todos os dados de todos os símbolos disponíveis, precisamos avisar o usuário sobre isso. Não faz sentido fazer isso na própria biblioteca, porque ela só precisa saber o que o usuário solicita, assim, esse aviso deve ser feito no manipulador OnInit() do programa.

Vamos fazer desta maneira, se nas configurações do EA for selecionado o modo para trabalhar com a lista completa de símbolos no servidor, o programa exibirá a janela padrão da função MessageBox() avisando

e propondo selecionar quer "Sim" para carregar a lista completa de símbolos quer "Não" para trabalhar apenas com o símbolo atual. O usuário precisará fazer apenas uma escolha: clicar em "Sim" e aguardar a criação da coleção com todos os símbolos disponíveis ou clicar em "Não" e trabalhar com o atual.

Escreveremos esta verificação com exibição da pregunta ao usuário no manipulador OnInit() do EA:

//--- Check if working with the full list is selected
   used_symbols_mode=InpModeUsedSymbols;
   if((ENUM_SYMBOLS_MODE)used_symbols_mode==SYMBOLS_MODE_ALL)
     {
      int total=SymbolsTotal(false);
      string ru_n="\nКоличество символов на сервере "+(string)total+".\nМаксимальное количество: "+(string)SYMBOLS_COMMON_TOTAL+" символов.";
      string en_n="\nThe number of symbols on server "+(string)total+".\nMaximal number: "+(string)SYMBOLS_COMMON_TOTAL+" symbols.";
      string caption=TextByLanguage("Внимание!","Attention!");
      string ru="Выбран режим работы с полным списком.\nВ этом режиме первичная подготовка списка коллекции символов может занять длительное время."+ru_n+"\nПродолжить?\n\"Нет\" - работа с текущим символом \""+Symbol()+"\"";
      string en="Full list mode selected.\nIn this mode, the initial preparation of the collection symbols list may take a long time."+en_n+"\nContinue?\n\"No\" - working with the current symbol \""+Symbol()+"\"";
      string message=TextByLanguage(ru,en);
      int flags=(MB_YESNO | MB_ICONWARNING | MB_DEFBUTTON2);
      int mb_res=MessageBox(message,caption,flags);
      switch(mb_res)
        {
         case IDNO : 
           used_symbols_mode=SYMBOLS_MODE_CURRENT; 
           break;
         default:
           break;
        }
     }

Neste caso, à variável global used_symbols_mode atribuímos o valor do modo de trabalho com símbolos, selecionado pelo usuário nas configurações do EA.
Se selecionado o modo de trabalho com uma lista completa
, criamos a mensagem da janela de aviso e exibimos esta janela na tela. Em seguida, verificamos qual botão clicou o usuário. Se for o botão "Não", à variável used_symbols_mode atribuímos o valor do modo de trabalho com o símbolo atual.
Em outros casos ("Sim" ou botão Esc), deixamos o modo de trabalho com a lista completa de símbolos disponíveis.

Em seguida, criamos uma array de símbolos usados (enviamos para a função de criação de array a variável used_symbols_mode):

//--- Fill in the array of used symbols
   used_symbols=InpUsedSymbols;
   CreateUsedSymbolsArray((ENUM_SYMBOLS_MODE)used_symbols_mode,used_symbols,array_used_symbols);

definimos o tipo de lista usada na biblioteca (modo de símbolo) e exibimos no log uma mensagem sobre o modo usado para trabalhar com símbolo:

//--- Set the type of the used symbol list in the symbol collection
   engine.SetUsedSymbols(array_used_symbols);
//--- Displaying the selected mode of working with the symbol object collection
   Print(engine.ModeSymbolsListDescription(),TextByLanguage(". Количество используемых символов: ",". Number of symbols used: "),engine.GetSymbolsCollectionTotal());

Como neste caso não é necessário, no manipulador OnInit() removemos o bloco de código de verificação rápida da coleção de símbolos:

//--- Fast check of the symbol object collection
   CArrayObj *list=engine.GetListAllUsedSymbols();
   CSymbol *symbol=NULL;
   if(list!=NULL)
     {
      int total=list.Total();
      for(int i=0;i<total;i++)
        {
         symbol=list.At(i);
         if(symbol==NULL)
            continue;
         symbol.Refresh();
         symbol.RefreshRates();
         symbol.PrintShort();
         if(InpModeUsedSymbols<SYMBOLS_MODE_MARKET_WATCH)
            symbol.Print();
        }
     }

Ao manipulador OnTick() adicionamos a variável para armazenar o último evento na coleção de símbolos e escrevemos (alteramos para os eventos da coleção) os blocos de processamento de eventos da conta e de eventos da coleção de símbolos:

//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//--- Initializing the last events
   static ENUM_TRADE_EVENT last_trade_event=WRONG_VALUE;
   static ENUM_ACCOUNT_EVENT last_account_event=WRONG_VALUE;
   static ENUM_SYMBOL_EVENT last_symbol_event=WRONG_VALUE;
//--- If working in the tester
   if(MQLInfoInteger(MQL_TESTER))
     {
      engine.OnTimer();
      PressButtonsControl();
     }
//--- If the last trading event changed
   if(engine.LastTradeEvent()!=last_trade_event)
     {
      last_trade_event=engine.LastTradeEvent();
      Comment("\nLast trade event: ",engine.GetLastTradeEventDescription());
      engine.ResetLastTradeEvent();
     }
//--- If there is an account event
   if(engine.IsAccountsEvent())
     {
      //--- the last account event
      last_account_event=engine.LastAccountEvent();
      //--- If this is a tester
      if(MQLInfoInteger(MQL_TESTER))
        {
         //--- Get the list of all account events occurred simultaneously
         CArrayObj* list=engine.GetListAccountEvents();
         if(list!=NULL)
           {
            //--- Get the next event in a loop
            int total=list.Total();
            for(int i=0;i<total;i++)
              {
               //--- take an event from the list
               CEventBaseObj *event=list.At(i);
               if(event==NULL)
                  continue;
               //--- Send an event to the event handler
               long lparam=event.LParam();
               double dparam=event.DParam();
               string sparam=event.SParam();
               OnDoEasyEvent(CHARTEVENT_CUSTOM+event.ID(),lparam,dparam,sparam);
              }
           }
        }
     }
//--- If there is a symbol collection event
   if(engine.IsSymbolsEvent())
     {
      //--- the last event in the symbol collection
      last_symbol_event=engine.LastSymbolsEvent();
      //--- If this is a tester
      if(MQLInfoInteger(MQL_TESTER))
        {
         //--- Get the list of all symbol events occurred simultaneously
         CArrayObj* list=engine.GetListSymbolsEvents();
         if(list!=NULL)
           {
            //--- Get the next event in a loop
            int total=list.Total();
            for(int i=0;i<total;i++)
              {
               //--- take an event from the list
               CEventBaseObj *event=list.At(i);
               if(event==NULL)
                  continue;
               //--- Send an event to the event handler
               long lparam=event.LParam();
               double dparam=event.DParam();
               string sparam=event.SParam();
               OnDoEasyEvent(CHARTEVENT_CUSTOM+event.ID(),lparam,dparam,sparam);
              }
           }
        }
     }
//--- If the trailing flag is set
   if(trailing_on)
     {
      TrailingPositions();
      TrailingOrders();
     }
  }
//+------------------------------------------------------------------+

Aqui tudo é simples e todas as ações necessárias para processar eventos daconta e da coleção de símbolos são comentadas na listagem.

Como se pode ver, agora o processamento de eventos é absolutamente o mesmo para todos os objetos, tanto para uma conta quanto para uma coleção de símbolos, tudo se resume a obter uma lista de eventos e enviar cada evento de turno da lista para o manipulador OnDoEasyEvent() do EA que processa eventos da biblioteca. Isso se tornou possível graças às alterações feitas na herança de objetos de biblioteca do objeto base CBaseObj, que implementa o processamento de eventos de objetos-herdeiros.

Ao manipulador do EA OnDoEasyEvent(), adicionamos o código de manipulação de eventos de coleção de símbolos:

//+------------------------------------------------------------------+
//| Handling DoEasy library events                                   |
//+------------------------------------------------------------------+
void OnDoEasyEvent(const int id,
                   const long &lparam,
                   const double &dparam,
                   const string &sparam)
  {
   int idx=id-CHARTEVENT_CUSTOM;
   string event="::"+string(idx);
   int digits=Digits();
//--- Handling trading events
   if(idx>TRADE_EVENT_NO_EVENT && idx<TRADE_EVENTS_NEXT_CODE)
     {
      event=EnumToString((ENUM_TRADE_EVENT)ushort(idx));
      digits=(int)SymbolInfoInteger(sparam,SYMBOL_DIGITS);
     }
//--- Handling account events
   else if(idx>ACCOUNT_EVENT_NO_EVENT && idx<ACCOUNT_EVENTS_NEXT_CODE)
     {
      Print(TimeMSCtoString(lparam)," ",sparam,": ",engine.GetAccountEventDescription((ENUM_ACCOUNT_EVENT)idx));
      
      //--- if this is an equity increase
      if((ENUM_ACCOUNT_EVENT)idx==ACCOUNT_EVENT_EQUITY_INC)
        {
         //--- Close a position with the highest profit exceeding zero when the equity exceeds the value,
         //--- specified in the CAccountsCollection::InitControlsParams() method for
         //--- the m_control_equity_inc variable tracking the equity growth by 15 units (by default)
         //--- AccountCollection file, InitControlsParams() method, string 1199
         
         //--- Get the list of all open positions
         CArrayObj* list_positions=engine.GetListMarketPosition();
         //--- Select positions with the profit exceeding zero
         list_positions=CSelect::ByOrderProperty(list_positions,ORDER_PROP_PROFIT_FULL,0,MORE);
         if(list_positions!=NULL)
           {
            //--- Sort the list by profit considering commission and swap
            list_positions.Sort(SORT_BY_ORDER_PROFIT_FULL);
            //--- Get the position index with the highest profit
            int index=CSelect::FindOrderMax(list_positions,ORDER_PROP_PROFIT_FULL);
            if(index>WRONG_VALUE)
              {
               COrder* position=list_positions.At(index);
               if(position!=NULL)
                 {
                  //--- Get a ticket of a position with the highest profit and close the position by a ticket
                  #ifdef __MQL5__
                     trade.PositionClose(position.Ticket());
                  #else 
                     PositionClose(position.Ticket(),position.Volume());
                  #endif 
                 }
              }
           }
        }
     }
     
//--- Handling symbol events
   else if(idx>SYMBOL_EVENT_NO_EVENT && idx<SYMBOL_EVENTS_NEXT_CODE)
     {
      string name="";
      //--- Market Watch window event
      if(idx<SYMBOL_EVENT_TRADE_DISABLE)
        {
         string descr=engine.GetMWEventDescription((ENUM_SYMBOL_EVENT)idx);
         name=(idx==SYMBOL_EVENT_MW_SORT ? "" : ": "+sparam);
         Print(TimeMSCtoString(lparam)," ",descr,name);
        }
      //--- Symbol event
      else
        {
         CSymbol *symbol=engine.GetSymbolObjByName(sparam);
         if(symbol!=NULL)
           {
            string descr=": "+symbol.EventDescription((ENUM_SYMBOL_EVENT)ushort(idx));
            Print(TimeMSCtoString(lparam)," ",sparam,descr);
           }
        }
     }
  }
//+------------------------------------------------------------------+


Existem apenas duas opções, processamento de eventos da janela "Observação do Mercado" e manipulação de eventos de símbolos de coleção.

Para eventos da janela Observação do Mercado
criamos o evento necessário
e o exibimos no log,
para eventos de símbolos
da lista obtemos o símbolo pelo seu nome
a partir do parâmetro dd string do evento sparam, do objeto-símbolo obtemos uma descrição de string de seu evento, adicionamo-o ao texto criado e exibimos o texto no log.
Não faremos outras ações adicionais para os testes.

Com isso são concluídas as alterações do EA de teste.
A listagem completa do EA pode ser vista nos arquivos anexados ao artigo.

Se executarmos o EA numa conta demo, após algum tempo poderemos ver entradas no log sobre alterações nas propriedades dos símbolos. Por exemplo, ao iniciar um EA na véspera da abertura de um pregão na segunda-feira, entradas sobre mudanças de spread de vários símbolos começam a ser exibidas ativamente no log.
Como exemplo, para apenas quatro símbolos na janela "Observação do Mercado", já faz uma hora que as mensagens sobre alterações no spread de símbolos piscam no log:

2019.07.15 04:02:24.167 TestDoEasyPart16 (EURUSD,H4)    Working with symbols from the "Market Watch" window. The number of symbols used: 4
2019.07.15 04:02:25.762 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:27.316 GBPUSD: Spread value in points decreased by -7 (351)
2019.07.15 04:02:31.259 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:32.676 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:02:33.761 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:35.218 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:02:46.261 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:47.680 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:02:48.761 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:50.222 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:02:53.760 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:55.305 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:02:56.760 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:02:58.221 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:03:01.261 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:02.683 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:03:03.760 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:05.226 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:03:16.260 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:17.673 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:03:18.789 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:20.219 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:03:30.832 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:32.686 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:03:33.819 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:35.219 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:03:38.820 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:39.926 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:03:41.821 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:43.221 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:03:45.820 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:47.673 USDCHF: Spread value in points increased by 4 (287)
2019.07.15 04:03:48.836 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:50.234 USDCHF: Spread value in points decreased by -4 (283)
2019.07.15 04:03:50.865 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:03:52.598 USDCHF: Spread value in points increased by 51 (334)
2019.07.15 04:03:58.867 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:00.450 EURUSD: Spread value in points decreased by -42 (50)
2019.07.15 04:03:58.868 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:00.430 USDCHF: Spread value in points decreased by -96 (238)
2019.07.15 04:03:59.417 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:00.934 USDCHF: Spread value in points increased by 22 (260)
2019.07.15 04:03:59.912 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:01.431 USDCHF: Spread value in points decreased by -5 (255)
2019.07.15 04:04:35.445 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:36.984 GBPUSD: Spread value in points decreased by -112 (239)
2019.07.15 04:04:35.445 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:36.985 EURUSD: Spread value in points decreased by -7 (43)
2019.07.15 04:04:35.445 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:04:36.984 USDCHF: Spread value in points decreased by -127 (128)
2019.07.15 04:04:58.460 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:05:00.102 GBPUSD: Spread value in points decreased by -207 (32)
2019.07.15 04:04:58.959 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:05:00.696 EURUSD: Spread value in points decreased by -4 (39)
2019.07.15 04:05:01.006 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:05:02.697 EURUSD: Spread value in points increased by 3 (42)
2019.07.15 04:05:02.037 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:05:03.686 EURUSD: Spread value in points decreased by -32 (10)

... muitas linhas ignoradas ...

2019.07.15 04:55:09.780 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:11.578 GBPUSD: Spread value in points decreased by -3 (29)
2019.07.15 04:55:09.780 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:11.478 USDCHF: Spread value in points increased by 4 (32)
2019.07.15 04:55:10.482 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:11.681 USDCHF: Spread value in points decreased by -3 (29)
2019.07.15 04:55:11.623 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:13.477 USDCHF: Spread value in points increased by 3 (32)
2019.07.15 04:55:12.111 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:13.884 USDCHF: Spread value in points decreased by -5 (27)
2019.07.15 04:55:13.626 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:15.275 USDCHF: Spread value in points increased by 4 (31)
2019.07.15 04:55:19.628 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:21.381 USDCHF: Spread value in points decreased by -3 (28)
2019.07.15 04:55:20.126 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:21.882 USDCHF: Spread value in points increased by 3 (31)
2019.07.15 04:55:28.659 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:30.292 EURUSD: Spread value in points increased by 3 (20)
2019.07.15 04:55:33.690 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:35.298 EURUSD: Spread value in points decreased by -3 (17)
2019.07.15 04:55:53.298 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:55.137 EURUSD: Spread value in points increased by 3 (20)
2019.07.15 04:55:53.826 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:55.643 EURUSD: Spread value in points decreased by -3 (17)
2019.07.15 04:55:54.906 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:56.632 USDCHF: Spread value in points decreased by -3 (28)
2019.07.15 04:55:55.912 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:57.536 USDCHF: Spread value in points increased by 4 (32)
2019.07.15 04:55:56.907 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:58.636 USDCHF: Spread value in points decreased by -4 (28)
2019.07.15 04:55:57.434 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:55:58.832 USDCHF: Spread value in points increased by 4 (32)
2019.07.15 04:55:59.949 TestDoEasyPart16 (EURUSD,H4)    2019.07.15 00:56:01.538 USDCHF: Spread value in points decreased by -3 (29)

Vamos agora executar o EA num testador com dois símbolo e ver quais entradas ele nos mostrará.

Nas configurações do testador para o parâmetro de entrada do EA Mode of used symbols list escolhemos na lista suspensa "Trabalhar com a lista de símbolos definida" e no parâmetro List of used symbols (comma - separator) digitamos dois símbolos separados por vírgulas: EURUSD, GBPUSD e executamos o teste visual do EA:


Os logs sobre eventos de ambos os símbolos são exibidos no log, em particular, sobre alterações nos valores de spread dos símbolos usados. Ao alterar as propriedades da conta (neste caso, ao aumentar os lucros atuais), no log também são exibidos os registros sobre isso e são fechadas as posições lucrativas.

O que vem agora?

No próximo artigo, faremos um acesso conveniente do programa para alterar os valores das propriedades controladas e monitoradas dos objetos com base na classe de objeto base CBaseObj.

Abaixo estão anexados todos os arquivos da versão atual da biblioteca e os arquivos do EA de teste. Você pode baixá-los e testar tudo sozinho.
Se você tiver perguntas, comentários e sugestões, poderá expressá-los nos comentários do artigo.

Complementos

Artigos desta série:

Parte 1. Conceito, gerenciamento de dados e primeiros resultados
Parte 2. Coleção do histórico de ordens e negócios
Parte 3. Coleção de ordens e posições de mercado, busca e ordenação
Parte 4. Eventos de Negociação. Conceito
Parte 5. Classes e coleções de eventos de negociação. Envio de eventos para o programa
Parte 6. Eventos da conta netting
Parte 7. Eventos de ativação da ordem stoplimit, preparação da funcionalidade para os eventos de modificação de ordens e posições
Parte 8. Eventos de modificação de ordens e posições
Parte 9. Compatibilidade com a MQL4 - preparação dos dados
Parte 10. Compatibilidade com a MQL4 - eventos de abertura de posição e ativação de ordens pendentes
Parte 11. Compatibilidade com a MQL4 - eventos de encerramento de posição
Parte 12. Implementação da classe de objeto "conta" e da coleção de objetos da conta
Parte 13. Eventos do objeto conta
Parte 14. O objeto símbolo
Parte 15. Coleção de objetos-símbolos


Traduzido do russo pela MetaQuotes Software Corp.
Artigo original: https://www.mql5.com/ru/articles/7071

Arquivos anexados |
MQL5.zip (224.58 KB)
MQL4.zip (224.58 KB)
Biblioteca para criação simples e rápida de programas para MetaTrader (Parte XV): coleção de objetos-símbolo Biblioteca para criação simples e rápida de programas para MetaTrader (Parte XV): coleção de objetos-símbolo

No artigo, consideramos a criação de uma coleção de símbolos com base no objeto-símbolo abstrato básico criado no último artigo. Os descendentes de símbolos abstratos vão esclarecer os dados do símbolo e definir a disponibilidade das propriedades básicas do objeto-símbolo no programa. Esses objetos-símbolos vão ser distinguidos por sua afiliação a grupos (status do símbolo).

Estudo dos padrões de Merrill Estudo dos padrões de Merrill

Neste artigo, nós examinaremos o modelo de padrões de Merrill e tentaremos avaliar qual a sua relevância atual. Para isso, nós desenvolveremos uma ferramenta para testar tais padrões e aplicar o modelo a vários tipos de dados, como preços de fechamento, máxima e mínima, além dos osciladores.

Bova abordagem para interpretar a divergência clássica e oculta. Parte II Bova abordagem para interpretar a divergência clássica e oculta. Parte II

Neste artigo, examinaremos criticamente a divergência clássica e analisaremos a eficácia de vários indicadores. Também oferecemos variantes de filtragem para aumentar a precisão da análise e continuar a considerar soluções não padrão. Como resultado, criaremos uma ferramenta atípica para resolver a tarefa em questão.

Está chegando o novo MetaTrader 5 e MQL5 Está chegando o novo MetaTrader 5 e MQL5

Esta é apenas uma breve resenha do MetaTrader 5. Eu não posso descrever todos os novos recursos do sistema por um período tão curto de tempo - os testes começaram em 09.09.2009. Esta é uma data simbólica, e tenho certeza que será um número de sorte. Alguns dias passaram-se desde que eu obtive a versão beta do terminal MetaTrader 5 e MQL5. Eu ainda não consegui testar todos os seus recursos, mas já estou impressionado.