CComboBox

CComboBox è una classe del controllo complesso ComboBox (con i controlli dipendenti).

Descrizione

ComboBox è costituito da un box elementi, combinato con un controllo statico, destinato alla selezione. La porzione lista-box del controllo può essere discesa quando l'utente seleziona la freccia a discesa accanto al controllo

Dichiarazione

   class CComboBox : public CWndContainer

Titolo

   #include <Controls\ComboBox.mqh>

Gerarchia di ereditarietà

  CObject

      CWnd

          CWndContainer

              CComboBox

Result of the code provided below:

ControlsComboBox

Metodi della Classe

Create

 

Create

Crea il controllo

Event handlers chart

 

OnEvent

Event Handler di tutti gli eventi del chart

Add

 

AddItem

Aggiunge un elemento

Impostazioni

 

ListViewItems

Imposta il numero di elementi, mostrato sul controllo

Data

 

Select

Seleziona elemento elenco aggiornato in base all'indice

SelectByText

Seleziona elemento della lista corrente per testo

SelectByValue

Seleziona elemento della lista corrente per valore

Di sola lettura dei dati

 

Value

Ottiene il valore dell'elemento della lista corrente

Controlli dipendenti

 

CreateEdit

Crea il controllo dipendente (edit)

CreateButton

Crea il controllo dipendente (bottone)

CreateList

Crea il controllo dipendente (visualizzazione elenco)

Event handlers dei controlli Dependent

 

OnClickEdit

"ClickEdit" event handler (virtual)

OnClickButton

"ClickButton" event handler (virtual)

OnChangeList

"ChangeList" event handler (virtual)

Show/Hide

 

ListShow

Mostra la lista di elementi

ListHide

Nasconde la lista di elementi

Example of creating a panel with Combobox control:

//+------------------------------------------------------------------+
//|                                             ControlsComboBox.mq5 |
//|                        Copyright 2015, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2015, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property description "Control Panels and Dialogs. Demonstration class CComboBox"
#include <Controls\Dialog.mqh>
#include <Controls\ComboBox.mqh>
//+------------------------------------------------------------------+
//| defines                                                          |
//+------------------------------------------------------------------+
//--- indents and gaps
#define INDENT_LEFT                         (11)      // indent from left (with allowance for border width)
#define INDENT_TOP                          (11)      // indent from top (with allowance for border width)
#define INDENT_RIGHT                        (11)      // indent from right (with allowance for border width)
#define INDENT_BOTTOM                       (11)      // indent from bottom (with allowance for border width)
#define CONTROLS_GAP_X                      (5)       // gap by X coordinate
#define CONTROLS_GAP_Y                      (5)       // gap by Y coordinate
//--- for buttons
#define BUTTON_WIDTH                        (100)     // size by X coordinate
#define BUTTON_HEIGHT                       (20)      // size by Y coordinate
//--- for the indication area
#define EDIT_HEIGHT                         (20)      // size by Y coordinate
//--- for group controls
#define GROUP_WIDTH                         (150)     // size by X coordinate
#define LIST_HEIGHT                         (179)     // size by Y coordinate
#define RADIO_HEIGHT                        (56)      // size by Y coordinate
#define CHECK_HEIGHT                        (93)      // size by Y coordinate
//+------------------------------------------------------------------+
//| Class CControlsDialog                                            |
//| Usage: main dialog of the Controls application                   |
//+------------------------------------------------------------------+
class CControlsDialog : public CAppDialog
  {
private:
   CComboBox         m_combo_box;;                    // CComboBox object
 
public:
                     CControlsDialog(void);
                    ~CControlsDialog(void);
   //--- create
   virtual bool      Create(const long chart,const string name,const int subwin,const int x1,const int y1,const int x2,const int y2);
   //--- chart event handler
   virtual bool      OnEvent(const int id,const long &lparam,const double &dparam,const string &sparam);
 
protected:
   //--- create dependent controls
   bool              CreateComboBox(void);
   //--- handlers of the dependent controls events
   void              OnChangeComboBox(void);
  };
//+------------------------------------------------------------------+
//| Event Handling                                                   |
//+------------------------------------------------------------------+
EVENT_MAP_BEGIN(CControlsDialog)
ON_EVENT(ON_CHANGE,m_combo_box,OnChangeComboBox)
EVENT_MAP_END(CAppDialog)
//+------------------------------------------------------------------+
//| Constructor                                                      |
//+------------------------------------------------------------------+
CControlsDialog::CControlsDialog(void)
  {
  }
//+------------------------------------------------------------------+
//| Destructor                                                       |
//+------------------------------------------------------------------+
CControlsDialog::~CControlsDialog(void)
  {
  }
//+------------------------------------------------------------------+
//| Create                                                           |
//+------------------------------------------------------------------+
bool CControlsDialog::Create(const long chart,const string name,const int subwin,const int x1,const int y1,const int x2,const int y2)
  {
   if(!CAppDialog::Create(chart,name,subwin,x1,y1,x2,y2))
      return(false);
//--- create dependent controls
   if(!CreateComboBox())
      return(false);
//--- succeed
   return(true);
  }
//+------------------------------------------------------------------+
//| Create the "ComboBox" element                                    |
//+------------------------------------------------------------------+
bool CControlsDialog::CreateComboBox(void)
  {
//--- coordinates
   int x1=INDENT_LEFT;
   int y1=INDENT_TOP+(EDIT_HEIGHT+CONTROLS_GAP_Y)+
          (BUTTON_HEIGHT+CONTROLS_GAP_Y)+
          (EDIT_HEIGHT+CONTROLS_GAP_Y);
   int x2=x1+GROUP_WIDTH;
   int y2=y1+EDIT_HEIGHT;
//--- create
   if(!m_combo_box.Create(m_chart_id,m_name+"ComboBox",m_subwin,x1,y1,x2,y2))
      return(false);
   if(!Add(m_combo_box))
      return(false);
//--- fill out with strings
   for(int i=0;i<16;i++)
      if(!m_combo_box.ItemAdd("Item "+IntegerToString(i)))
         return(false);
//--- succeed
   return(true);
  }
//+------------------------------------------------------------------+
//| Event handler                                                    |
//+------------------------------------------------------------------+
void CControlsDialog::OnChangeComboBox(void)
  {
   Comment(__FUNCTION__+" \""+m_combo_box.Select()+"\"");
  }
//+------------------------------------------------------------------+
//| Global Variables                                                 |
//+------------------------------------------------------------------+
CControlsDialog ExtDialog;
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- create application dialog
   if(!ExtDialog.Create(0,"Controls",0,40,40,380,344))
      return(INIT_FAILED);
//--- run application
   ExtDialog.Run();
//--- succeed
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//--- 
   Comment("");
//--- destroy dialog
   ExtDialog.Destroy(reason);
  }
//+------------------------------------------------------------------+
//| Expert chart event function                                      |
//+------------------------------------------------------------------+
void OnChartEvent(const int id,         // event ID  
                  const long& lparam,   // event parameter of the long type
                  const double& dparam, // event parameter of the double type
                  const string& sparam) // event parameter of the string type
  {
   ExtDialog.ChartEvent(id,lparam,dparam,sparam);
  }