Q99848: INFO: Use ON_MESSAGE() Macro to Map Less-Common Messages

Article: Q99848
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,1.51,1.52,2.0,2.1,4.0,5.0,6.0,7.0
Operating System(s): 
Keyword(s): kbMFC kbVC100 kbVC150 kbVC200 kbVC400 kbVC600 kbWndwMsg kbGrpDSMFCATL kbArchitecture
Last Modified: 15-MAY-2002

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft C/C++ for MS-DOS, version 7.0 
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52 
   - Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 5.0, 6.0 
   - Microsoft Visual C++.NET (2002) 
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SUMMARY
=======

The Microsoft Foundation Class Library includes macros that an application can
include in the message map of a CWnd or CWnd derived object.These macros, such
as ON_WM_PAINT() and ON_WM_SIZE(), map common messages to default handler
functions. The Microsoft Foundation Class Library provides macros for all
standard window messages. To process user-defined message or less-common window
messages (like WM_COMMNOTIFY), use the ON_MESSAGE() macro. The ON_MESSAGE macro
must be used in a CWnd derived class. For example, it cannot be used in a
CWinApp class or a CDocument class because neither of these classes is derived
from CWnd.

MORE INFORMATION
================

Here's an example of how an application could use ON_MESSAGE:

    // inside the class declaration
    afx_msg LRESULT OnMyMessage(WPARAM wParam, LPARAM lParam);

    ...

    #define WM_MYMESSAGE (WM_USER + 100)

    BEGIN_MESSAGE_MAP(CMyWnd, CMyParentWndClass)
       ON_MESSAGE(WM_MYMESSAGE, OnMyMessage)
    END_MESSAGE_MAP()

    LRESULT CMyWnd::OnMyMessage(WPARAM WParam, LPARAM LParam)
    {
       return (LRESULT)0;
    }

The function specified by the second parameter of the ON_MESSAGE macro must be a
function that takes two parameters, a WPARAM and an LPARAM, and returns a
LRESULT. For more information about the ON_MESSAGE() macro, see Technical Note
#6 in the MFC Tech Notes Help file distributed with Microsoft Visual C++ version
1.0 and in the MFC Technical Notes included in the Visual C++ Books Online. Or
search the Visual C++ Books Online on the keyword "ON_MESSAGE."

Additional query words: kbinf 7.00 1.00 1.50 2.00 2.10 2.50 2.51 2.52 3.00 3.10 4.00

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Keywords          : kbMFC kbVC100 kbVC150 kbVC200 kbVC400 kbVC600 kbWndwMsg kbGrpDSMFCATL kbArchitecture 
Technology        : kbAudDeveloper kbMFC
Version           : :1.0,1.5,1.51,1.52,2.0,2.1,4.0,5.0,6.0,7.0
Issue type        : kbinfo

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