The SBJ MVC Framework - The Design View, Responding to Model Change

//------------------------------------------------------------------------------
// $Workfile: CmdMsgHandler.h $
// $Header:  $
//
//	Copyright � 2008 SbjCat
// All rights reserved.
//
//
// *** Authors ***
//	 Steve Johnson
//
// $Revision: $
//
//-----------------------------------------------------------------------------

#pragma once

#include "MessageHandler.h"
#include "CmdTargetController.h"

namespace SbjCore
{
	namespace Mvc
	{
		class CmdTargetController;

		/**
		CmdMsgHandler is an abstract class derived from MessageHandler 
		for handling WM_COMMAND messages in the Mvc Framework.  For 
		information on how message handling differs in the Mvc framework 
		from that in the MFC framework, see the Mvc overview. 

		CmdMsgHandler objects are added to the handler map maintained 
		by CmdTargetController and derivative classes.  They are keyed by 
		the message ID(s) they handle. 

		The CmdTargetController calls the CmdMsgHandler's public methods 
		for handling not only the Cmd, but also the CmdUI messages. 

		CmdMsgHandler public methods in turn call virtual private methods 
		that are overridden in derived classes.  These private methods are 
		where the messages are actually handled; whether by default 
		implementation in the CmdMsgHandler class itself or the implementation 
		in the derived class. 

		The private OnHandleCmd method is a pure virtual and must be 
		implemented in the derived class.  The OnHandleCmdUI method has a 
		default implementation that returns true for the Enable method of 
		the CCmdUI object it handles.  

		To support the functionality derived from its base MessageHandler
		class for the chaining of handlers, derived OnHandleCmd and 
		OnHandleCmdUI methods should call the public methods HandleCmdPrev
		and HandleCmdUIPrev as appropriate.

		*/
		class AFX_EXT_CLASS CmdMsgHandler : public MessageHandler
		{
		public:
			virtual ~CmdMsgHandler();
			
			CmdTargetController* GetController() const;
		public:
			bool HandleCmd(UINT nID);
			bool HandleCmdUI(CCmdUI* pCmdUI);
			bool HandleCmdPrev(UINT nID);
			bool HandleCmdUIPrev(CCmdUI* pCmdUI);
		private:
			virtual bool OnHandleCmd(UINT nID) = 0;								
			virtual bool OnHandleCmdUI(CCmdUI* pCmdUI);
		};
	}		
}

//*** Modification History ***
// $Log:  $