This macro indicates which function will handle a user-interface update command message.
ON_UPDATE_COMMAND_UI(id, memberFxn )
The message ID.
The name of the message-handler function to which the message is mapped.
There should be exactly one ON_UPDATE_COMMAND_UI macro statement in your message map for every user-interface update command that must be mapped to a message-handler function.
For more information and examples, see Message Handling and Mapping Topics.
Header: afxole.h