00000016.txt

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   How subclass the listbox portion of a combobox? 
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   The listbox portion of a combobox is of type COMBOLBOX  ( notice the 
 'L'). 
 Because the ComboLBox window is not a child of the ComboBox window, it is 
 not obvious how to subclass the COMBOLBOX control.  Luckily, under the 
 Win32 
 API, Windows sends a message to the COMBOBOX ( notice no 'L') called 
 WM_CTLCOLORLISTBOX before the listbox is drawn. The lParam passed with this 
 message contains the handle of the listbox. For example: 
  
 LRESULT CFileUpdateCombo::OnCtlColorListBox(WPARAM wParam, 
  
 LPARAM lParam) 
  
 { 
  
         if ( ! m_bSubclassedListBox ) 
  
 { 
  
                         HWND hWnd = (HWND)lParam; 
  
                         CWnd* pWnd = FromHandle(hWnd); 
  
                         if ( pWnd && pWnd != this ) 
  
                         { 
  
                                 // m_ListBox is derived from CListBox 
                                 m_ListBox.SubclassWindow(hWnd ); 
  
                                 m_ListBox.SetOwner(this); 
  
                                 m_bSubclassedListBox = TRUE; 
  
                         } 
  
         } 
  
         return (LRESULT)GetStockObject(WHITE_BRUSH); 
  
 } 
 
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