FIX: MFC Doesn't Call CPrintDialog::OnInitDialog

• The Microsoft Foundation Classes (MFC), included with:
  • Microsoft Visual C++, 32-bit Editions, version 6.0

SYMPTOMS

The OnInitDialog() function (which is called in response to a WM_INITDIALOG message) for a CPrintDialog-derived class, was called in MFC prior to Visual C++ 6.0. However, this is no longer true for MFC DLLs of Visual C++ 6.0. Therefore, programs that rely on OnInitDialog() to be called will not work as expected.

CAUSE

Previously, MFC set up a message hook for CPrintDialog. This hook was the only way to catch a WM_INITDIALOG message. MFC for Visual C++ 6.0 purposely removed this hook so MFC applications would automatically get the new Print dialog by default on Windows NT 5.0; however, this causes applications that rely on CPringDialog::OnInitDialog() to fail to work.

RESOLUTION

Set up the message hook function, _AfxCommDlgProc(), in the constructor of your CPrintDialog-derived class as shown below:

   // CMyPrintDialog is a CPrintDialog-derived class.
   CMyPrintDialog::CMyPrintDialog(DWORD dwFlags)
   : CPrintDialog(FALSE,dwFlags)
   {
      //{{AFX_DATA_INIT(CMyPrintDialog)
      //}}AFX_DATA_INIT
      // MFCBUG: MFC 6.0 doesn't set the message hook!
      m_pd.Flags |= PD_ENABLEPRINTHOOK | PD_ENABLESETUPHOOK;
      // _AfxCommDlgProc is exported from static MFC libraries
      m_pd.lpfnPrintHook = _AfxCommDlgProc;
      m_pd.lpfnSetupHook = _AfxCommDlgProc;
   } 

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in the Visual Studio 6.0 Service Pack 1.

To obtain this service pack, please see:

http://msdn.microsoft.com/vstudio/sp/default.asp

Q193009 INFO: Visual Studio 6.0 Service Pack 1 Readme

Q194022 INFO: Visual Studio 6.0 Service Packs What, Where, Why

Q194295 HOWTO: Tell That Visual Studio 6.0 Service Pack Is Installed

MORE INFORMATION

Steps to Reproduce Behavior

1. Derive a class from CPrintDialog.



2. Add a message handler for WM_INITDIALOG in the CPrintDialog-derived class. The message handler OnInitDialog() is not called in Visual C++ 6.0.

© Microsoft Corporation 1998, All Rights Reserved.
Contributions by Yeong-Kah Tam, Microsoft Corporation

Keywords : kbVC600 kbVS600sp2 kbVS600sp2bug kbVS600sp2fix kbVS600SP1fix kbMFC600bug kbVC600SP1Fix
Version : winnt:6.0
Platform : winnt
Issue type : kbbug