总结二、MFC消息映射

1、消息映射的现实

// 下面为MFC中定义的一些宏，可自行查看相应的头文件#ifdef _ATL_ENABLE_PTM_WARNING#define PTM_WARNING_DISABLE#define PTM_WARNING_RESTORE#else#define PTM_WARNING_DISABLE \__pragma(warning( push )) \__pragma(warning( disable : 4867 ))#define PTM_WARNING_RESTORE \__pragma(warning( pop ))#endif //_ATL_ENABLE_PTM_WARNING// pointer to afx_msg member function#ifndef AFX_MSG_CALL#define AFX_MSG_CALL#endiftypedef void (AFX_MSG_CALL CCmdTarget::*AFX_PMSG)(void);// like 'AFX_PMSG' but for CWnd-derived classes onlytypedef void (AFX_MSG_CALL CWnd::*AFX_PMSGW)(void);// like 'AFX_PMSG' but for CWinThread-derived classes onlytypedef void (AFX_MSG_CALL CWinThread::*AFX_PMSGT)(void);struct AFX_MSGMAP_ENTRY{UINT nMessage;   // windows messageUINT nCode;      // control code or WM_NOTIFY codeUINT nID;        // control ID (or 0 for windows messages)UINT nLastID;    // used for entries specifying a range of control id'sUINT_PTR nSig;   // signature type (action) or pointer to message #AFX_PMSG pfn;    // routine to call (or special value)};struct AFX_MSGMAP{const AFX_MSGMAP* (PASCAL* pfnGetBaseMap)();const AFX_MSGMAP_ENTRY* lpEntries;};// 这里即息映射宏的主体#define BEGIN_MESSAGE_MAP(theClass, baseClass) \PTM_WARNING_DISABLE \const AFX_MSGMAP* theClass::GetMessageMap() const \{ return GetThisMessageMap(); } \const AFX_MSGMAP* PASCAL theClass::GetThisMessageMap() \{ \typedef theClass ThisClass;   \typedef baseClass TheBaseClass;   \static const AFX_MSGMAP_ENTRY _messageEntries[] =  \{#define END_MESSAGE_MAP() \{0, 0, 0, 0, AfxSig_end, (AFX_PMSG)0 } \}; \static const AFX_MSGMAP messageMap = \{ &TheBaseClass::GetThisMessageMap, &_messageEntries[0] }; \return &messageMap; \}  \PTM_WARNING_RESTORE#define ON_WM_SYSCOMMAND() \{ WM_SYSCOMMAND, 0, 0, 0, AfxSig_vwl, \(AFX_PMSG)(AFX_PMSGW) \(static_cast< void (AFX_MSG_CALL CWnd::*)(UINT, LPARAM) > ( &ThisClass :: OnSysCommand)) },// 根据上面的宏定义，可将下面的宏进行展开BEGIN_MESSAGE_MAP(CTestDlg, CDialog)ON_WM_SYSCOMMAND()ON_WM_PAINT()ON_BN_CLICKED(IDC_BUTTON_MESSAGE, &CTestDlg::OnBnClickedButtonMessage)ON_NOTIFY(LVN_ITEMCHANGED, IDC_LIST, &CTestDlg::OnLvnItemchangedList)END_MESSAGE_MAP()   const AFX_MSGMAP* theClass::GetMessageMap() const {       return GetThisMessageMap(); } const AFX_MSGMAP* PASCAL theClass::GetThisMessageMap() { typedef theClass ThisClass;   typedef baseClass TheBaseClass;static const AFX_MSGMAP_ENTRY _messageEntries[] =  {{ WM_SYSCOMMAND, 0, 0, 0, AfxSig_vwl, (AFX_PMSG)(AFX_PMSGW)(static_cast<void (AFX_MSG_CALL CWnd::*)(UINT, LPARAM)>(&ThisClass::OnSysCommand)) },{ WM_PAINT, 0, 0, 0, AfxSig_vv, (AFX_PMSG)(AFX_PMSGW)(static_cast<void (AFX_MSG_CALL CWnd::*)(void)>(&ThisClass::OnPaint)) },{ WM_COMMAND, (WORD)wNotifyCode, (WORD)id, (WORD)id, AfxSigCmd_v, (static_cast<AFX_PMSG>(memberFxn)) },{ WM_NOTIFY, (WORD)(int)wNotifyCode, (WORD)id, (WORD)id, AfxSigNotify_v, (AFX_PMSG)(static_cast<void (AFX_MSG_CALL CCmdTarget::*)(NMHDR*, LRESULT*)>(memberFxn)) },{ 0, 0, 0, 0, AfxSig_end, (AFX_PMSG)0 } }; static const AFX_MSGMAP messageMap = { &TheBaseClass::GetThisMessageMap, &_messageEntries[0] }; return &messageMap; }

2、扩展（自定义）消息

// afxmsg_.h// User extensions for message map entries// for Windows messages#define ON_MESSAGE(message, memberFxn) \{ message, 0, 0, 0, AfxSig_lwl, \(AFX_PMSG)(AFX_PMSGW) \(static_cast< LRESULT (AFX_MSG_CALL CWnd::*)(WPARAM, LPARAM) > \(memberFxn)) },// for Registered Windows messages#define ON_REGISTERED_MESSAGE(nMessageVariable, memberFxn) \{ 0xC000, 0, 0, 0, (UINT_PTR)(UINT*)(&nMessageVariable), \/*implied 'AfxSig_lwl'*/ \(AFX_PMSG)(AFX_PMSGW) \(static_cast< LRESULT (AFX_MSG_CALL CWnd::*)(WPARAM, LPARAM) > \(memberFxn)) },// for Thread messages#define ON_THREAD_MESSAGE(message, memberFxn) \{ message, 0, 0, 0, AfxSig_vwl, \(AFX_PMSG)(AFX_PMSGT) \(static_cast< void (AFX_MSG_CALL CWinThread::*)(WPARAM, LPARAM) > \(memberFxn)) },// for Registered Windows messages#define ON_REGISTERED_THREAD_MESSAGE(nMessageVariable, memberFxn) \{ 0xC000, 0, 0, 0, (UINT_PTR)(UINT*)(&nMessageVariable), \/*implied 'AfxSig_vwl'*/ \(AFX_PMSG)(AFX_PMSGT) \(static_cast< void (AFX_MSG_CALL CWinThread::*)(WPARAM, LPARAM) > \(memberFxn)) },

3、消息调用的实现（参见wincore.cpp）

BOOL CWnd::OnWndMsg(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pResult){LRESULT lResult = 0;union MessageMapFunctions mmf;mmf.pfn = 0;CInternalGlobalLock winMsgLock;// special case for commandsif (message == WM_COMMAND){if (OnCommand(wParam, lParam)){lResult = 1;goto LReturnTrue;}return FALSE;}// special case for notifiesif (message == WM_NOTIFY){NMHDR* pNMHDR = (NMHDR*)lParam;if (pNMHDR->hwndFrom != NULL && OnNotify(wParam, lParam, &lResult))goto LReturnTrue;return FALSE;}// special case for activationif (message == WM_ACTIVATE)_AfxHandleActivate(this, wParam, CWnd::FromHandle((HWND)lParam));// special case for set cursor HTERRORif (message == WM_SETCURSOR &&_AfxHandleSetCursor(this, (short)LOWORD(lParam), HIWORD(lParam))){lResult = 1;goto LReturnTrue;}   // special case for windows that contain windowless ActiveX controls   BOOL bHandled;   bHandled = FALSE;   if ((m_pCtrlCont != NULL) && (m_pCtrlCont->m_nWindowlessControls > 0))   {  if (((message >= WM_MOUSEFIRST) && (message <= AFX_WM_MOUSELAST)) || ((message >= WM_KEYFIRST) && (message <= WM_IME_KEYLAST)) || ((message >= WM_IME_SETCONTEXT) && (message <= WM_IME_KEYUP)))  { bHandled = m_pCtrlCont->HandleWindowlessMessage(message, wParam, lParam, &lResult);  }   }   if (bHandled)   {  goto LReturnTrue;   }const AFX_MSGMAP* pMessageMap; pMessageMap = GetMessageMap();UINT iHash; iHash = (LOWORD((DWORD_PTR)pMessageMap) ^ message) & (iHashMax-1);winMsgLock.Lock(CRIT_WINMSGCACHE);AFX_MSG_CACHE* pMsgCache; pMsgCache = &_afxMsgCache[iHash];const AFX_MSGMAP_ENTRY* lpEntry;if (message == pMsgCache->nMsg && pMessageMap == pMsgCache->pMessageMap){// cache hitlpEntry = pMsgCache->lpEntry;winMsgLock.Unlock();if (lpEntry == NULL)return FALSE;// cache hit, and it needs to be handledif (message < 0xC000)goto LDispatch;elsegoto LDispatchRegistered;}else{// not in cache, look for itpMsgCache->nMsg = message;pMsgCache->pMessageMap = pMessageMap;for (/* pMessageMap already init'ed */; pMessageMap->pfnGetBaseMap != NULL;pMessageMap = (*pMessageMap->pfnGetBaseMap)()){// Note: catch not so common but fatal mistake!!//      BEGIN_MESSAGE_MAP(CMyWnd, CMyWnd)ASSERT(pMessageMap != (*pMessageMap->pfnGetBaseMap)());if (message < 0xC000){// constant window messageif ((lpEntry = AfxFindMessageEntry(pMessageMap->lpEntries,message, 0, 0)) != NULL){pMsgCache->lpEntry = lpEntry;winMsgLock.Unlock();goto LDispatch;}}else{// registered windows messagelpEntry = pMessageMap->lpEntries;while ((lpEntry = AfxFindMessageEntry(lpEntry, 0xC000, 0, 0)) != NULL){UINT* pnID = (UINT*)(lpEntry->nSig);ASSERT(*pnID >= 0xC000 || *pnID == 0);// must be successfully registeredif (*pnID == message){pMsgCache->lpEntry = lpEntry;winMsgLock.Unlock();goto LDispatchRegistered;}lpEntry++;      // keep looking past this one}}}pMsgCache->lpEntry = NULL;winMsgLock.Unlock();return FALSE;}LDispatch:ASSERT(message < 0xC000);mmf.pfn = lpEntry->pfn;switch (lpEntry->nSig){default:ASSERT(FALSE);break;case AfxSig_l_p:{CPoint point(lParam);lResult = (this->*mmf.pfn_l_p)(point);break;}case AfxSig_b_D_v:lResult = (this->*mmf.pfn_b_D)(CDC::FromHandle(reinterpret_cast<HDC>(wParam)));break;case AfxSig_b_b_v:lResult = (this->*mmf.pfn_b_b)(static_cast<BOOL>(wParam));break;case AfxSig_b_u_v:lResult = (this->*mmf.pfn_b_u)(static_cast<UINT>(wParam));break;case AfxSig_b_h_v:lResult = (this->*mmf.pfn_b_h)(reinterpret_cast<HANDLE>(wParam));break;case AfxSig_i_u_v:lResult = (this->*mmf.pfn_i_u)(static_cast<UINT>(wParam));break;case AfxSig_C_v_v:lResult = reinterpret_cast<LRESULT>((this->*mmf.pfn_C_v)());break;case AfxSig_v_u_W:(this->*mmf.pfn_v_u_W)(static_cast<UINT>(wParam), CWnd::FromHandle(reinterpret_cast<HWND>(lParam)));break;case AfxSig_u_u_v:lResult = (this->*mmf.pfn_u_u)(static_cast<UINT>(wParam));break;case AfxSig_b_v_v:lResult = (this->*mmf.pfn_b_v)();break;case AfxSig_b_W_uu:lResult = (this->*mmf.pfn_b_W_u_u)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)),LOWORD(lParam), HIWORD(lParam));break;case AfxSig_b_W_COPYDATASTRUCT:lResult = (this->*mmf.pfn_b_W_COPYDATASTRUCT)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)),reinterpret_cast<COPYDATASTRUCT*>(lParam));break;case AfxSig_b_v_HELPINFO:lResult = (this->*mmf.pfn_b_HELPINFO)(reinterpret_cast<LPHELPINFO>(lParam));break;case AfxSig_CTLCOLOR:{// special case for OnCtlColor to avoid too many temporary objectsASSERT(message == WM_CTLCOLOR);AFX_CTLCOLOR* pCtl = reinterpret_cast<AFX_CTLCOLOR*>(lParam);CDC dcTemp; dcTemp.m_hDC = pCtl->hDC;CWnd wndTemp; wndTemp.m_hWnd = pCtl->hWnd;UINT nCtlType = pCtl->nCtlType;// if not coming from a permanent window, use stack temporaryCWnd* pWnd = CWnd::FromHandlePermanent(wndTemp.m_hWnd);if (pWnd == NULL){#ifndef _AFX_NO_OCC_SUPPORT// determine the site of the OLE control if it is oneCOleControlSite* pSite;if (m_pCtrlCont != NULL && (pSite = (COleControlSite*)m_pCtrlCont->m_siteMap.GetValueAt(wndTemp.m_hWnd)) != NULL){wndTemp.m_pCtrlSite = pSite;}#endifpWnd = &wndTemp;}HBRUSH hbr = (this->*mmf.pfn_B_D_W_u)(&dcTemp, pWnd, nCtlType);// fast detach of temporary objectsdcTemp.m_hDC = NULL;wndTemp.m_hWnd = NULL;lResult = reinterpret_cast<LRESULT>(hbr);}break;case AfxSig_CTLCOLOR_REFLECT:{// special case for CtlColor to avoid too many temporary objectsASSERT(message == WM_REFLECT_BASE+WM_CTLCOLOR);AFX_CTLCOLOR* pCtl = reinterpret_cast<AFX_CTLCOLOR*>(lParam);CDC dcTemp; dcTemp.m_hDC = pCtl->hDC;UINT nCtlType = pCtl->nCtlType;HBRUSH hbr = (this->*mmf.pfn_B_D_u)(&dcTemp, nCtlType);// fast detach of temporary objectsdcTemp.m_hDC = NULL;lResult = reinterpret_cast<LRESULT>(hbr);}break;case AfxSig_i_u_W_u:lResult = (this->*mmf.pfn_i_u_W_u)(LOWORD(wParam),CWnd::FromHandle(reinterpret_cast<HWND>(lParam)), HIWORD(wParam));break;case AfxSig_i_uu_v:lResult = (this->*mmf.pfn_i_u_u)(LOWORD(wParam), HIWORD(wParam));break;case AfxSig_i_W_uu:lResult = (this->*mmf.pfn_i_W_u_u)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)),LOWORD(lParam), HIWORD(lParam));break;case AfxSig_i_v_s:lResult = (this->*mmf.pfn_i_s)(reinterpret_cast<LPTSTR>(lParam));break;case AfxSig_l_w_l:lResult = (this->*mmf.pfn_l_w_l)(wParam, lParam);break;case AfxSig_l_uu_M:lResult = (this->*mmf.pfn_l_u_u_M)(LOWORD(wParam), HIWORD(wParam), CMenu::FromHandle(reinterpret_cast<HMENU>(lParam)));break;case AfxSig_v_b_h:    (this->*mmf.pfn_v_b_h)(static_cast<BOOL>(wParam), reinterpret_cast<HANDLE>(lParam));break;case AfxSig_v_h_v:    (this->*mmf.pfn_v_h)(reinterpret_cast<HANDLE>(wParam));break;case AfxSig_v_h_h:    (this->*mmf.pfn_v_h_h)(reinterpret_cast<HANDLE>(wParam), reinterpret_cast<HANDLE>(lParam));break;case AfxSig_v_v_v:(this->*mmf.pfn_v_v)();break;case AfxSig_v_u_v:(this->*mmf.pfn_v_u)(static_cast<UINT>(wParam));break;case AfxSig_v_u_u:(this->*mmf.pfn_v_u_u)(static_cast<UINT>(wParam), static_cast<UINT>(lParam));break;case AfxSig_v_uu_v:(this->*mmf.pfn_v_u_u)(LOWORD(wParam), HIWORD(wParam));break;case AfxSig_v_v_ii:(this->*mmf.pfn_v_i_i)(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));break;case AfxSig_v_u_uu:(this->*mmf.pfn_v_u_u_u)(static_cast<UINT>(wParam), LOWORD(lParam), HIWORD(lParam));break;case AfxSig_v_u_ii:(this->*mmf.pfn_v_u_i_i)(static_cast<UINT>(wParam), LOWORD(lParam), HIWORD(lParam));break;case AfxSig_v_w_l:(this->*mmf.pfn_v_w_l)(wParam, lParam);break;case AfxSig_MDIACTIVATE:(this->*mmf.pfn_v_b_W_W)(m_hWnd == reinterpret_cast<HWND>(lParam),CWnd::FromHandle(reinterpret_cast<HWND>(lParam)),CWnd::FromHandle(reinterpret_cast<HWND>(wParam)));break;case AfxSig_v_D_v:(this->*mmf.pfn_v_D)(CDC::FromHandle(reinterpret_cast<HDC>(wParam)));break;case AfxSig_v_M_v:(this->*mmf.pfn_v_M)(CMenu::FromHandle(reinterpret_cast<HMENU>(wParam)));break;case AfxSig_v_M_ub:(this->*mmf.pfn_v_M_u_b)(CMenu::FromHandle(reinterpret_cast<HMENU>(wParam)),GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));break;case AfxSig_v_W_v:(this->*mmf.pfn_v_W)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)));break;case AfxSig_v_v_W:(this->*mmf.pfn_v_W)(CWnd::FromHandle(reinterpret_cast<HWND>(lParam)));break;case AfxSig_v_W_uu:(this->*mmf.pfn_v_W_u_u)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)), LOWORD(lParam),HIWORD(lParam));break;case AfxSig_v_W_p:{CPoint point(lParam);(this->*mmf.pfn_v_W_p)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)), point);}break;case AfxSig_v_W_h:(this->*mmf.pfn_v_W_h)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)),reinterpret_cast<HANDLE>(lParam));break;case AfxSig_ACTIVATE:(this->*mmf.pfn_v_u_W_b)(LOWORD(wParam),CWnd::FromHandle(reinterpret_cast<HWND>(lParam)), HIWORD(wParam));break;case AfxSig_SCROLL:case AfxSig_SCROLL_REFLECT:{// special case for WM_VSCROLL and WM_HSCROLLASSERT(message == WM_VSCROLL || message == WM_HSCROLL ||message == WM_VSCROLL+WM_REFLECT_BASE || message == WM_HSCROLL+WM_REFLECT_BASE);int nScrollCode = (short)LOWORD(wParam);int nPos = (short)HIWORD(wParam);if (lpEntry->nSig == AfxSig_SCROLL)(this->*mmf.pfn_v_u_u_W)(nScrollCode, nPos,CWnd::FromHandle(reinterpret_cast<HWND>(lParam)));else(this->*mmf.pfn_v_u_u)(nScrollCode, nPos);}break;case AfxSig_v_v_s:(this->*mmf.pfn_v_s)(reinterpret_cast<LPTSTR>(lParam));break;case AfxSig_v_u_cs:(this->*mmf.pfn_v_u_cs)(static_cast<UINT>(wParam), reinterpret_cast<LPCTSTR>(lParam));break;case AfxSig_OWNERDRAW:(this->*mmf.pfn_v_i_s)(static_cast<int>(wParam), reinterpret_cast<LPTSTR>(lParam));lResult = TRUE;break;case AfxSig_i_i_s:lResult = (this->*mmf.pfn_i_i_s)(static_cast<int>(wParam), reinterpret_cast<LPTSTR>(lParam));break;case AfxSig_u_v_p:{CPoint point(lParam);lResult = (this->*mmf.pfn_u_p)(point);}break;case AfxSig_u_v_v:lResult = (this->*mmf.pfn_u_v)();break;case AfxSig_v_b_NCCALCSIZEPARAMS:(this->*mmf.pfn_v_b_NCCALCSIZEPARAMS)(static_cast<BOOL>(wParam), reinterpret_cast<NCCALCSIZE_PARAMS*>(lParam));break;case AfxSig_v_v_WINDOWPOS:(this->*mmf.pfn_v_v_WINDOWPOS)(reinterpret_cast<WINDOWPOS*>(lParam));break;case AfxSig_v_uu_M:(this->*mmf.pfn_v_u_u_M)(LOWORD(wParam), HIWORD(wParam), reinterpret_cast<HMENU>(lParam));break;case AfxSig_v_u_p:{CPoint point(lParam);(this->*mmf.pfn_v_u_p)(static_cast<UINT>(wParam), point);}break;case AfxSig_SIZING:(this->*mmf.pfn_v_u_pr)(static_cast<UINT>(wParam), reinterpret_cast<LPRECT>(lParam));lResult = TRUE;break;case AfxSig_MOUSEWHEEL:lResult = (this->*mmf.pfn_b_u_s_p)(LOWORD(wParam), (short)HIWORD(wParam),CPoint(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)));if (!lResult)return FALSE;break;case AfxSig_MOUSEHWHEEL:(this->*mmf.pfn_MOUSEHWHEEL)(LOWORD(wParam), (short)HIWORD(wParam),CPoint(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)));break;case AfxSig_l:lResult = (this->*mmf.pfn_l_v)();if (lResult != 0)return FALSE;break;case AfxSig_u_W_u:lResult = (this->*mmf.pfn_u_W_u)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)), static_cast<UINT>(lParam));break;case AfxSig_v_u_M:(this->*mmf.pfn_v_u_M)(static_cast<UINT>(wParam), CMenu::FromHandle(reinterpret_cast<HMENU>(lParam)));break;case AfxSig_u_u_M:lResult = (this->*mmf.pfn_u_u_M)(static_cast<UINT>(wParam), CMenu::FromHandle(reinterpret_cast<HMENU>(lParam)));break;case AfxSig_u_v_MENUGETOBJECTINFO:lResult = (this->*mmf.pfn_u_v_MENUGETOBJECTINFO)(reinterpret_cast<MENUGETOBJECTINFO*>(lParam));break;case AfxSig_v_M_u:(this->*mmf.pfn_v_M_u)(CMenu::FromHandle(reinterpret_cast<HMENU>(wParam)), static_cast<UINT>(lParam));break;case AfxSig_v_u_LPMDINEXTMENU:(this->*mmf.pfn_v_u_LPMDINEXTMENU)(static_cast<UINT>(wParam), reinterpret_cast<LPMDINEXTMENU>(lParam));break;case AfxSig_APPCOMMAND:(this->*mmf.pfn_APPCOMMAND)(CWnd::FromHandle(reinterpret_cast<HWND>(wParam)), static_cast<UINT>(GET_APPCOMMAND_LPARAM(lParam)), static_cast<UINT>(GET_DEVICE_LPARAM(lParam)), static_cast<UINT>(GET_KEYSTATE_LPARAM(lParam)));lResult = TRUE;break;case AfxSig_RAWINPUT:(this->*mmf.pfn_RAWINPUT)(static_cast<UINT>(GET_RAWINPUT_CODE_WPARAM(wParam)), reinterpret_cast<HRAWINPUT>(lParam));break;case AfxSig_u_u_u:lResult = (this->*mmf.pfn_u_u_u)(static_cast<UINT>(wParam), static_cast<UINT>(lParam));break;case AfxSig_MOUSE_XBUTTON:(this->*mmf.pfn_MOUSE_XBUTTON)(static_cast<UINT>(GET_KEYSTATE_WPARAM(wParam)), static_cast<UINT>(GET_XBUTTON_WPARAM(wParam)), CPoint(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)));lResult = TRUE;break;case AfxSig_MOUSE_NCXBUTTON:(this->*mmf.pfn_MOUSE_NCXBUTTON)(static_cast<short>(GET_NCHITTEST_WPARAM(wParam)), static_cast<UINT>(GET_XBUTTON_WPARAM(wParam)), CPoint(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)));lResult = TRUE;break;case AfxSig_INPUTLANGCHANGE:(this->*mmf.pfn_INPUTLANGCHANGE)(static_cast<UINT>(wParam), static_cast<UINT>(lParam));lResult = TRUE;break;case AfxSig_INPUTDEVICECHANGE:(this->*mmf.pfn_INPUTDEVICECHANGE)(GET_DEVICE_CHANGE_LPARAM(wParam), reinterpret_cast<HANDLE>(lParam));break;case AfxSig_v_u_hkl:(this->*mmf.pfn_v_u_h)(static_cast<UINT>(wParam), reinterpret_cast<HKL>(lParam));break;}goto LReturnTrue;LDispatchRegistered:    // for registered windows messagesASSERT(message >= 0xC000);ASSERT(sizeof(mmf) == sizeof(mmf.pfn));mmf.pfn = lpEntry->pfn;lResult = (this->*mmf.pfn_l_w_l)(wParam, lParam);LReturnTrue:if (pResult != NULL)*pResult = lResult;return TRUE;}

总结

1、MFC的消息映射即关于消息与消息处理函数之间的一张静态表。

2、自定义消息
（1）定义消息
#define WM_MYMSG_TEST  WM_USER + 1000
（2）添加消息映射
BEGIN_MESSAGE_MAP(CTestDlg, CDialog)
ON_MESSAGE(WM_MYMSG_TEST, OnMyMsgTest)
END_MESSAGE_MAP()
（3）声明消息处理函数
afx_msg LRESULT OnMyMsgTest(WPARAM wParam, LPARAM lParam);
（4）实现消息处理函数
LRESULT OnMyMsgTest(WPARAM wParam, LPARAM lParam)
{
MessageBox("Hello, world!");

return 0;
}