MFC message transmission Sequence

1. afxwndproc () This function is used to receive messages, locate the cwnd object to which the message belongs, and then call afxcallwndproc.

2. afxcallwndproc () This function is used to save messages (the content mainly contains message identifiers and message parameters) for future use,
Then call the windowproc () function.

3. windowproc () this function is responsible for sending messages to the onwndmsg () function. If not processed, call the defwindowproc () function.

4. onwndmsg () This function first sorts messages by byte. For wm_command messages, oncommand () messages are called.
Response Function for wm_notify messages
Call the onnotify () Message response function. Any missed message is a window message. Onwndmsg () function search
To find
The processing function that can process any window message. If the onwndmsg () function cannot find such a processing function
Returns a message to the windowproc () function, which sends the message to the defwindowproc () function.

5. oncommand () This function checks whether this is a control notification (the lparam parameter is not null. If the lparam parameter is null, it indicates
The message is not a control notification). If it is, the oncommand () function tries to map the message to the control that creates the notification;
If it is not a control notification (or if the control rejects the ing message) oncommand (), the on1_msg () function will be called.

6. Based on the class that receives messages, the onreceivmsg () function is potentially used in a process called command routing.
Send command messages and control notifications.
For example, if the class that owns the window is a framework class, the command and notification messages are also transmitted to the view and document class for
Class to find a message processing function