Article ID: 99848 - View products that this article applies to.
This article was previously published under Q99848
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.
Here's an example of how an application could use ON_MESSAGE:
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."
Article ID: 99848 - Last Review: November 21, 2006 - Revision: 3.1