FIX: Assert in Appui1.cpp Line 215 in MFC SDI/MDI Application

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

SYMPTOMS

When you try to display a modal window without explicitly specifying a parent in a command handler of an MFC SDI/MDI application, where the frame window is destroyed in the command handler before displaying the modal window, you might get an assertion in CCmdTarget::GetRoutingFrame_() (Appui1.cpp line: 215) with debug builds.

In the release builds of the application, modal windows may behave similar to modeless windows. This will also be the case if you update an MFC application from Visual C== 5.0 to Visual C++ 6.0 (both versions of Visual C++ use the MFC DLL named MFC42.dll).

CAUSE

Modal windows now use the routing frame data member (m_pRoutingFrame) of the thread state to decide on the owner in GetSafeOwner(). The problem is that the CFrameWnd set as the thread state's current routing frame is deleted, but the thread state is not updated to reflect that fact.

RESOLUTION

Set the thread state's current routing frame to NULL in the destructor of your CFrameWnd derived class that is being destroyed:

CMyFrameWnd::~CMyFrameWnd()
   {

      if( AfxGetThreadState()->m_pRoutingFrame == this )
      {
         AfxGetThreadState()->m_pRoutingFrame = NULL;
      }
   } 

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

For more information on the Visual Studio 6.0 Service Pack 1, please see the following articles in the Microsoft Knowledge Base:

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 Packs Are Installed

MORE INFORMATION

The MFC frame windows affected by this problem can be of type CFrameWnd, CMDIFrameWnd, CMDIChildWnd, and COleIPFrameWnd.

The MFC modal windows affected are:

• Dialog



• CPropertySheet



• Ole Property Sheet [invoked through [ASCII 150] OleObject::DoVerb(OLEIVERB_PROPERTIES)]



• COleBusyDialog



• Message Box [invoked through AfxMessageBox()]



• MAPI modal window [when calling MAPISendMail()]



• SQL Driver Connection dialog box [when calling SQLDriverConnect()]

Steps to Reproduce Behavior

1. Use AppWizard to generate an MFC exe that is an MDI-based application.



2. Use ClassWizard to override OnCloseDocument of the CDocument class generated by AppWizard.



3. Edit the OnCloseDocument member function as shown here:
   
   

   
         void CMyDoc::OnCloseDocument()
         {
            CDocument::OnCloseDocument();
            AfxMessageBox("The Document is Closed");
         } 




4. Build and run the application.



5. On the File menu, click Close.

"Debug Assertion Failed! File: Appui1.cpp line: 215".

CChildFrame::~CChildFrame()
   {

      if( AfxGetThreadState()->m_pRoutingFrame == this )
      {
         AfxGetThreadState()->m_pRoutingFrame = NULL;
      }
   } 

Additional query words: connect MfcDocView

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