Q74795: HOWTO: Use PeekMessage() Loops in a Dialog Box

Article: Q74795
Product(s): Microsoft Windows Software Development Kit
Version(s): 3.0,3.1
Operating System(s): 
Keyword(s): kbcode kbDlg kbGrpDSUser kbOSWin310 kbWndw kbWndwMsg kbFAQ kbOSWin300 kbwin16sdkfaq
Last Modified: 04-FEB-2002

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SUMMARY
=======

When a modal dialog box is created, Windows uses its own message loop, which is
stored in USER. If the application takes responsibility for processing messages
[using a PeekMessage() loop], then IsDialogMessage() must be used to pass
appropriate messages to the dialog box.

The following code fragment demonstrates the correct technique:

   bFlag = TRUE;

    while ((bFlag) || (PeekMessage(&message, hDlg, 0, 0, PM_REMOVE)))
      {
      if (!IsDialogMessage(hDlg, &message))
        {
        TranslateMessage(&message);
        DispatchMessage(&message);
        }
      }

If technique is not used, accelerator keys in the dialog box will not function
properly.

For additional information on the proper use of PeekMessage() loops, please see
the following articles in the Microsoft Knowledge Base:

  Q67293 Some CTRL Accelerator Keys Conflict with Edit Controls

  Q108936 Using a Dialog Box as the Main Window of an Application

Additional query words:

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Keywords          : kbcode kbDlg kbGrpDSUser kbOSWin310 kbWndw kbWndwMsg kbFAQ kbOSWin300 kbwin16sdkfaq 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : :3.0,3.1
Issue type        : kbhowto

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