Trying to pass object to class from CArrayObj Object need help in understanding what I am doing wrong

[Scott Watson]

 Hello Everyone,

 

I am looking for some help with the below code, I am trying to pass an object to a different class from a CArrayObj class using the At method which returns an object.

But so far everything I have tried gives a critical crash stating access to an invalid pointer. So how can I make this code work, what am I missing?

Thank you for your Time

EK 

 

//+------------------------------------------------------------------+
//|                                                        Test2.mq5 |
//|                        Copyright 2010, MetaQuotes Software Corp. |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2010, MetaQuotes Software Corp."
#property link      "http://www.mql5.com"
#property version   "1.00"
#property indicator_chart_window

#include <Object.mqh>
//#include <Arrays\ArrayObj.mgh>
#include "C:\Program Files\MetaTrader 5\MQL5\Include\Arrays\ArrayObj.mqh"

class A : public CObject
{
   public:
      string test_str;
      int test_int;
      float test_float;
   
   // constructor
   void A()    {test_str = "0"; test_int = 0; test_float = 0.0;}
   // function
   void Set_Values(A *nNew);
   
   
};

void A::Set_Values(A *nNew)
{
   test_str = nNew.test_str;   
}

class B
{
   public:
      A *MyA; // my instance of Cass A
      
      // constructor
      void B()    { MyA = new A; }
      
      //function
      void Set_MyObject(A *NewObj);
      
};

void B::Set_MyObject(A *NewObj)
{
   MyA.test_str = NewObj.test_str;
   MyA.test_int = NewObj.test_int;
   MyA.test_float = NewObj.test_float;
}

CArrayObj *MyListOfObjects;
B *ThisIsMyB;

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
   int i;
   
   // Create 10 new Objects of Class A and puts them in our ArrayObj List
   for(i = 0; i<10; i++)
   {
      A *Temp = new A;
      MyListOfObjects.Add(Temp);
   }
   
   // now lets say I wanted to make  one from my list and give it to Class B
   // ** but this gives invalid pointer access ***
   ThisIsMyB.Set_MyObject(MyListOfObjects.At(7));  

   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime& time[],
                const double& open[],
                const double& high[],
                const double& low[],
                const double& close[],
                const long& tick_volume[],
                const long& volume[],
                const int& spread[])
  {
//---
//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+

[Rashid Umarov]

Where is

MyListOfObjects =new CArrayObj;

?

Read articles:

• The Order of Object Creation and Destruction in MQL5
• Using the Object Pointers in MQL5

[Scott Watson]

Rosh:

Where is

?

Read articles:

• The Order of Object Creation and Destruction in MQL5
• Using the Object Pointers in MQL5

Hello Rosh,

 

Thank you that helped a lot, I was able to track my problem down :)

 

Thanks

EK