why my programs end during onClose event?

Hi everyone,
there is something that I'm not very clear about. Why do my program close when I click the cross button on the top right hand corner where I had comment the on PostMessage for the following code below? And also, why when I Post WM_DESTORY, my dialog did not close?

Code:

void CMYDlg::OnClose() 
{	
  int returnValue=IDNO;
  retValue = ::MessageBox(NULL, _T("You are about to close the application, are you sure you want to continue?"), 
							_T("Testing"), MB_YESNO|MB_ICONQUESTION);
  if(returnValue == IDYES)
  {
	 ::PostMessage(0,WM_DESTROY,NULL,NULL);
  }
  CDialog::OnClose();
}

CDialog::OnCLose() will call the code to destroy your Dlg.

Try something like....

Code:

void CMYDlg::OnClose() 
{	
  int returnValue=IDNO;
  retValue = ::MessageBox(NULL, _T("You are about to close the application, are you sure you want to continue?"), 
							_T("Testing"), MB_YESNO|MB_ICONQUESTION);
  if(returnValue == IDYES)
  {
	 CDialog::OnClose();  
  }
  
}

1) Suggest you don't post messages directly in a MFC app - suggest you use proper functions such as EndDialog or call the base function's member.
2) There's no use in using ::MessageBox since you can just use MessageBox which is relative to your window. You are just passing NULL, which is usually just done where there's no window, so in this case use CWnd's MessageBox and don't worry about the HWND.