[MFC]比較安全的殺Modeless Dialog方法

在結束dialog之前，先在PostNcDestroy()內下PostMessage()或是SendMessage給()Parent Dialog來將pointer設成NULL。
之後再刪除this，這樣也比較不會發生modeless dialog內的destructor動作沒做完前，因Parent Dialog刪除modeless dialog而造成不定時的crash事件。

PostNcDestroy可以在IDDProperties裡面設定就可用了

Sample code
PostNcDestory

void CMDXBatchJobManagerDlg::PostNcDestroy()
{
   // TODO: Add your specialized code here and/or call the base class

   CDialog::PostNcDestroy();

   ::AfxGetMainWnd()->PostMessage(WM_MDLESSDLG_CLOSE);
   //::AfxGetMainWnd()->SendMessage(WM_MDLESSDLG_CLOSE);

   delete this;
}

OnPostMessage

LRESULT CMDXBatchJobManagerDlg::OnPostMessage(WPARAM wParam, LPARAM lParam)
{
   m_pModelessDlg = NULL;   //Set null. It will be delete by itself
   return TRUE;
}

message map
in header file

#define WM_MDLESSDLG_CLOSE 10058 //Any unique value

in cpp

BEGIN_MESSAGE_MAP(CMDXBatchJobManagerDlg, CDialog)
   ON_MESSAGE(WM_MDLESSDLG_CLOSE, PostNcDestroy)
END_MESSAGE_MAP()