About the message flow in the MFC is divided into 3 categories: WM_COMMAND: All UI components and acceleration keys generate this message, all derived CCMDTARGETs have the ability to process the message standard message: WM_XX outside WM_COMMAND The message is all standard messages, and the class derived in CWnd has the ability to handle the message control notification message: the message used to send to the parent window.
In the establishment of the MFC message mapping table, through a set of macros, you can make your class to handle some Windows messages in the parent class. This behavior is very like virtual functions, but the content we overload is not a virtual function. But the message.
