Re: Question of newbie: why an Avs occurs?

Hi,

Can I replace a class simply with its subclass?

I have done some test like this:

First I define a subclass of CEdit.

  class CWzdEdit:public CEdit{
    BOOL PreTranslateMessage(MSG *pMsg);
  };

  BOOL CWzdEdit::PreTranslateMessage(MSG *pMsg)
  {
    return CEdit::PreTranslageMessage(pMsg);
  }

Then I place two edit control on the dialog with the resource editor and
generate the DoDataExchange. Then I replace the "CEdit" with "CWzdEdit".

 class CWzdDialog : public CDialog{
 public:
    CWzdEdit m_ctrlWzd1;
    CWzdEdit m_ctrlWzd2;
    virtual void DoDataExchange(CDataExchange* pDX);
 };

 void CWzdDialog::DoDataExchange(CDataExchange* pDX){
    DDX_Control(pDX, IDC_EDIT_WZD1, m_ctrlWzd1);
    DDX_Control(pDX, IDC_EDIT_WZD2, m_ctrlWzd2);
 }

But an AVs occurs after I close the dialog even I do nothing. What's wrong
with my code?

Thank in advanced.

bucher