HOWTO: How to Access a Subclassed Windows Control in an OLE Control

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1. Add a member variable of type CListBox to the declaration of the COleControl derived class:

      class CSubclassCtrl : public COleControl
      {
      ...
      // Implementation
      protected:
   
        CListBox  m_ListBox;
      ...
      }
   						

2. Override the OnCreate member of the COleControl derived class and initialize the m_hWnd member of the CListBox member:

      int CSubclassCtrl::OnCreate(LPCREATESTRUCT lpCreateStruct)
      {
      if (COleControl::OnCreate(lpCreateStruct) == -1)
      return -1;
   
      m_ListBox.m_hWnd = m_hWnd;
   
        // Additional list box initialization can go here.
   
      return 0;
      }
   						

3. Set the m_hWnd member of the CListBox member to NULL in the destructor of the COleControl derived class:

      CSubclassCtrl::~CSubclassCtrl()
      {
        m_ListBox.m_hWnd = NULL;
      }
   						

   m_ListBox.InsertString(nIndex, _T("A String"));