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Message Categories

     Mesasge Category

Description

     Windows Messages

These are standard Windows messages that
     

begin with the WM_ prefix, with the exception of WM_COMMAND
     

messages. Examples of Windows messages are WM_PAINT, which
     

indicates that you need to redraw the client area of a window.

     Control Notification Messages

These are WM_COMMAND messages sent
     

from controls (such as a list box) to the window that created the
     

control or from a child window to a parent window. Parameters
     

associated with a WM_COMMAND message enable messages from the
     

controls in your application to be differentiated.

     Command Messages

These are also WM_COMMAND messages that
     

originate from the user interface elements, such as menu items and
     

toolbar buttons. MFC defines unique identifiers for standard menu
     

and toolbar command messages.


     The first two categories of message that you saw above, that is,
     standard Windows messages and control notification messages, are
     always handled by objects of classes derived from CWnd. Frame
     window classes and view classes, for example, are derived from
     CWnd, so they can have member functions to handle Windows messages
     and control notification messages.
     
     Handling command messages is much more flexible. Command messages
     that arise from menus and toolbars can be handled in any class
     that’s derived from CCmdTarget. For an SDI program, the sequence
     in which classes are offered an opportunity to handle a command message is:

       1. The view object

       2. The document object

       3. The document template object

       4. The main frame window object

       5. The application object
     
     The sequence for routing a command message in an MDI program is:

       1. The active view object

       2. The document object associated with the active view

       3. The document template object for the active document

       4. The frame window object for the active view

       5. The main frame window object

       6. The application object


   http://www.cnblogs.com/WarrenTang/archive/2008/04/23/1166994.html

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※ 來源: DISP BBS (http://disp.twbbs.org)
※ 作者: ott  來自: 118.166.4.170  時間: 2010-01-13 16:00:04