仿MFC消息映射框架

MFC的消息映射机制实际是由一个类自定义的函数列表来完成，中间有些小技巧需要注意

OwnMessageMapDef.h

 #ifndef _OWN_MESSAGE_MAP_DEF_H#define _OWN_MESSAGE_MAP_DEF_H//########################################################################// Own message map define// Created by Lifei//////////////////////////////////////////////////////////////////////////enum OwnSig{OwnSig_end = 0,OwnSig_v_v = 1,OwnSig_v_i = 2,OwnSig_v_pc_i = 3,OwnSig_i_pc_i = 4,};//////////////////////////////////////////////////////////////////////////class COwnMessageMap;typedef void (COwnMessageMap::*OWN_PMSG)(void);typedef void (COwnMessageMap::*OWN_PMSG_V_I)(int);typedef void (COwnMessageMap::*OWN_PMSG_V_PCHAR_I)(char*, int);typedef int (COwnMessageMap::*OWN_PMSG_I_PCHAR_I)(char*, int);union MessageMapFunctions{OWN_PMSG pfn;OWN_PMSG_V_I pfn_v_i;OWN_PMSG_V_PCHAR_I pfn_v_pc_i;OWN_PMSG_I_PCHAR_I pfn_i_pc_i;};//////////////////////////////////////////////////////////////////////////struct OWN_MSGMAP_ENTRY{unsigned int nMessage;OwnSig ownSig;OWN_PMSG pfn;};struct OWN_MSGMAP{const OWN_MSGMAP* (__stdcall* pfnGetBaseMap)();const OWN_MSGMAP_ENTRY* lpEntries;};//////////////////////////////////////////////////////////////////////////#define ON_OWN_COMMAND(id, pfn) /{ id, OwnSig_v_v, (OWN_PMSG)(pfn) },#define ON_OWN_COMMAND_V_I(id, pfn) /{ id, OwnSig_v_i, (OWN_PMSG)(OWN_PMSG_V_I)(pfn) },//////////////////////////////////////////////////////////////////////////#define DECLARE_OWN_MESSAGE_MAP() /protected: /virtual const OWN_MSGMAP* GetMessageMap() const; /static const OWN_MSGMAP* __stdcall GetThisMessageMap();#define BEGIN_OWN_MESSAGE_MAP(theClass, baseClass) /const OWN_MSGMAP* theClass::GetMessageMap() const /{ return GetThisMessageMap(); } /const OWN_MSGMAP* __stdcall theClass::GetThisMessageMap() /{ /typedef theClass ThisClass; /typedef baseClass TheBaseClass; /static const OWN_MSGMAP_ENTRY _messageEntries[] = /{#define END_MESSAGE_MAP() /{ -1, OwnSig_end, (OWN_PMSG)0 } /}; /static const OWN_MSGMAP messageMap = /{ &TheBaseClass::GetThisMessageMap, &_messageEntries[0] }; /return &messageMap; /}#endif

 

OwnMessageMap.h

#pragma once#include "OwnMessageMapDef.h"class COwnMessageMap{public:COwnMessageMap(void);virtual ~COwnMessageMap(void);public:int HandleMessage(unsigned int nID, char* pData, int nSize, int& nRet);DECLARE_OWN_MESSAGE_MAP()};

 

OwnMessageap.cpp

#include "StdAfx.h"#include "OwnMessageMap.h"//////////////////////////////////////////////////////////////////////////COwnMessageMap::COwnMessageMap(void){}COwnMessageMap::~COwnMessageMap(void){}//////////////////////////////////////////////////////////////////////////const OWN_MSGMAP* COwnMessageMap::GetMessageMap() const{return 0;}const OWN_MSGMAP* __stdcall COwnMessageMap::GetThisMessageMap(){ return 0;}//////////////////////////////////////////////////////////////////////////int COwnMessageMap::HandleMessage(unsigned int nID, char* pData, int nSize, int& nRet){const OWN_MSGMAP* pMsgMap = GetMessageMap();while (pMsgMap != 0){unsigned int nItem = 0;while (pMsgMap->lpEntries[nItem].nMessage != -1){if (pMsgMap->lpEntries[nItem].nMessage == nID){MessageMapFunctions mmf;mmf.pfn = pMsgMap->lpEntries[nItem].pfn;if (pMsgMap->lpEntries[nItem].ownSig == OwnSig_end)return 0;else if (pMsgMap->lpEntries[nItem].ownSig == OwnSig_v_v)(this->*mmf.pfn)();else if (pMsgMap->lpEntries[nItem].ownSig == OwnSig_v_i)(this->*mmf.pfn_v_i)(20); // testelse if (pMsgMap->lpEntries[nItem].ownSig == OwnSig_v_pc_i)(this->*mmf.pfn_v_pc_i)(pData, nSize);else if (pMsgMap->lpEntries[nItem].ownSig == OwnSig_i_pc_i)nRet = (this->*mmf.pfn_i_pc_i)(pData, nSize);return 0;}++nItem;}pMsgMap = (*pMsgMap->pfnGetBaseMap)();}return -1;}

 

 

实例代码

#pragma once#include "OwnMessageMap.h"class CTestMessage : public COwnMessageMap{public:CTestMessage(void);~CTestMessage(void);void TestVoid();void TestInt(int nItem);DECLARE_OWN_MESSAGE_MAP()};///////////////////////////////////////////////////#include "StdAfx.h"#include "TestMessage.h"#include <iostream>#include <string>using namespace std;//////////////////////////////////////////////////////////////////////////BEGIN_OWN_MESSAGE_MAP(CTestMessage, COwnMessageMap)ON_OWN_COMMAND(1, &CTestMessage::TestVoid)ON_OWN_COMMAND_V_I(2, &CTestMessage::TestInt)END_MESSAGE_MAP()//////////////////////////////////////////////////////////////////////////CTestMessage::CTestMessage(void){}CTestMessage::~CTestMessage(void){}void CTestMessage::TestVoid(){cout << "TestVoid" << endl;}void CTestMessage::TestInt(int nItem){cout << "TestInt " << nItem << endl;}

 

要点：

1.#define ON_OWN_COMMAND_V_I(id, pfn) /
                   { id, OwnSig_v_i, (OWN_PMSG)(OWN_PMSG_V_I)(pfn) },

这里存在两次强转，第一次转型为基类对应的成员函数类型，第二次转型为void成员函数指针

 

2.#define DECLARE_OWN_MESSAGE_MAP() /
     protected: /
           virtual const OWN_MSGMAP* GetMessageMap() const; /
           static const OWN_MSGMAP* __stdcall GetThisMessageMap();

派生类重写虚方法，基类直接返回一个空指针即可

 

3.union MessageMapFunctions的使用，参考MFC实现