Re: AfxMessageBox returns immediately without displaying the box

From:
"Jonathan Wood" <jwood@softcircuits.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Wed, 22 Aug 2007 12:39:07 -0600
Message-ID:
<OA1JLvO5HHA.4964@TK2MSFTNGP06.phx.gbl>
Yeah, I was able to repro this. Here's the solution:

"In MFC dialog-based application, when user closes main dialog,
WM_QUIT message is posted. That means, application exits the
message loop and any other window cannot be shown after this."

"Move your message boxes to your dialog OnOK and OnCancel
message handlers."
http://www.codeguru.com/forum/archive/index.php/t-237347.html

--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com

"Bogdan" <nouser@nodomain.com> wrote in message
news:e8XJFpN5HHA.5164@TK2MSFTNGP05.phx.gbl...

The problem is more obvious that I initially thought. It seems that
calling AfxMessageBox() after dismissing the app's dialog always returns
IDOK without displaying the box. This is regardless of the code returned
from the app's dialog box.

The following InitInstance() from a newly generated test app illustrates
the problem.

// CTestMsgBoxApp initialization

BOOL CTestMsgBoxApp::InitInstance()

{

// InitCommonControlsEx() is required on Windows XP if an application

// manifest specifies use of ComCtl32.dll version 6 or later to enable

// visual styles. Otherwise, any window creation will fail.

INITCOMMONCONTROLSEX InitCtrls;

InitCtrls.dwSize = sizeof(InitCtrls);

// Set this to include all the common control classes you want to use

// in your application.

InitCtrls.dwICC = ICC_WIN95_CLASSES;

InitCommonControlsEx(&InitCtrls);

CWinApp::InitInstance();

AfxEnableControlContainer();

// Standard initialization

// If you are not using these features and wish to reduce the size

// of your final executable, you should remove from the following

// the specific initialization routines you do not need

// Change the registry key under which our settings are stored

// TODO: You should modify this string to be something appropriate

// such as the name of your company or organization

SetRegistryKey(_T("Local AppWizard-Generated Applications"));

CTestMsgBoxDlg dlg;

m_pMainWnd = &dlg;

INT_PTR nResponse = dlg.DoModal();

if (nResponse == IDOK)

{

// TODO: Place code here to handle when the dialog is

// dismissed with OK

}

else if (nResponse == IDCANCEL)

{

// TODO: Place code here to handle when the dialog is

// dismissed with Cancel

}

nResponse = AfxMessageBox(L"First box", MB_OK | MB_ICONSTOP);

// Since the dialog has been closed, return FALSE so that we exit the

// application, rather than start the application's message pump.

return FALSE;

}

"Jonathan Wood" <jwood@softcircuits.com> wrote in message
news:uQDSEaN5HHA.1992@TK2MSFTNGP03.phx.gbl...

Okay, so did you trace through it in the debugger? What strings are
actually being passed to MessageBox? Does ReportError() work? Does
MessageBox() work outside of the catch block?

--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com

"Bogdan" <nouser@nodomain.com> wrote in message
news:eH$cIXN5HHA.1168@TK2MSFTNGP02.phx.gbl...

The code in my original message is just a pseudo code.

The CMyException class is not derived from MFC's CException. It is our
in-house non-mfc class that is used extensively in other non-mfc
projects. Sorry for the confusion.

Please note that a call to ::MessageBox() with constant strings (i.e.
ignoring exception object entirely) exhibits the same behaviour at the
point.

thx.

"Jonathan Wood" <jwood@softcircuits.com> wrote in message
news:OWdeANN5HHA.1148@TK2MSFTNGP05.phx.gbl...

CException::GetErrorMessage() returns BOOL so that would cause serious
problems and I can't imagine how that could ever compile without
errors. I'm sure ::MessageBox() isn't too crazy about NULL either. You
need to pass a valid string argument, and it would be nice if it
compiles too.

My catch blocks look like this:

e->ReportError();
e->Delete();

Nice and simple.

--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com

"Bogdan" <nouser@nodomain.com> wrote in message
news:uInxuGN5HHA.3916@TK2MSFTNGP02.phx.gbl...

Hi,

This is a pseudo code from InitInstance() of my dialog based app:

 if (cmdInfo.m_strAppName.IsEmpty()) {
   AfxMessageBox(IDS_SYNTAX, MB_OK | MB_ICONSTOP); // <= works
fine!
   return FALSE;
 }

 try {
   /* ... */
   CMyDlg dlg;
   m_pMainWnd = &dlg;
   INT_PTR nResponse = dlg.DoModal();
   if (nResponse == IDOK) {

       /* ... */ // might throw CMyException

       } else if (nResponse == IDCANCEL) {
           // TODO: Place code here to handle when the dialog is
           // dismissed with Cancel
       }
   } catch (CMyException& e) {
       // Neither of the calls below will display the box
       //nResponse = AfxMessageBox(e.GetErrorMessage(), MB_OK |
MB_ICONSTOP);
       nResponse = ::MessageBox(NULL, L"Text", L"Caption", MB_OK |
MB_ICONSTOP);
   }

The problem is that whenever exception is thrown I could hear a beep
but the message box is not displayed. Both Afx.. and Win API
functions return immediately with ret code set to 1 (IDOK).

Could someone please give me some idea what might be causing that
behaviour?

Thanks,
Bogdan

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