VC编程技术大型项目源码.doc

MFC消息机制首先,让我们看一下MFC的消息循环部分：（程序取自MFC源程序，由于篇幅，我删去了一些非重要的部分。）MFC的WinMain函数：cextern C int WINAPI_tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,LPTSTR lpCmdLine, int nCmdShow)/ call shared/exported WinMainreturn AfxWinMain(hInstance, hPrevInstance, lpCmdLine, nCmdShow); int AFXAPI AfxWinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)int nReturnCode = -1;CWinApp* pApp = AfxGetApp(); / / Perform specific initializationsif (!pApp-InitInstance()/ /初始化实例不成功，通常一个Dialog Based MFC程序必须返回FALSE/这样就可以跳过消息循环。nReturnCode = pApp-ExitInstance();goto InitFailure; nReturnCode = pApp-Run(); /进入消息循环部分 InitFailure:/ / 程序结束AfxWinTerm();return nReturnCode; int CWinApp:Run()/ return CWinThread:Run(); / 消息循环被封装在CWinThread类里。 int CWinThread:Run()BOOL bIdle = TRUE;LONG lIdleCount = 0; / 死循环，只有收到 WM_QUIT 消息后才会退出。for (;)while (bIdle &!:PeekMessage(&m_msgCur, NULL, NULL, NULL, PM_NOREMOVE)if (!OnIdle(lIdleCount+)bIdle = FALSE;/ 如果消息队列中没有消息，那么就调用OnIdle函数/ 否则，发送消息doif (!PumpMessage()/ PumpMessage函数仅在收到WM_QUIT消息才返回FALSEreturn ExitInstance(); / 退出死循环 if (IsIdleMessage(&m_msgCur)bIdle = TRUE;lIdleCount = 0; while (:PeekMessage(&m_msgCur, NULL, NULL, NULL, PM_NOREMOVE);/ 这段程序不仅完成了消息的发送，还实现了Idle功能。/ GetMessage函数在消息队列中没有消息时，将不会返回，/ 而是将控制权交给操作系统，直到消息队列中有消息为止。/ 这段程序在一开始就调用PeekMessage函数来检测消息队列中/ 是否有消息存在，如果存在就发送消息，/ 否则就意味着空闲，那么就调用OnIdle函数，/ 这样做，控制权永远不会交给操作系统。/ 由于Windows 95, NT都是抢占式的操作系统，/ 系统会自动进行任务切换。/ 所以不用担心别的程序不会被运行。 BOOL CWinThread:PumpMessage()if (!:GetMessage(&m_msgCur, NULL, NULL, NULL)/ 收到 WM_QUIT 消息，就返回 FALSE。return FALSE; / 否则就发送消息if (m_msgCur.message != WM_KICKIDLE & !PreTranslateMessage(&m_msgCur):TranslateMessage(&m_msgCur);:DispatchMessage(&m_msgCur);return TRUE;/c主程序的流程：text(程序开始)|vWinMain|vAfxWinMain|v FALSECWinApp:InitInstance- 退出程序|TRUE|vCWinApp:Run|vCWinThread:Run|OnIdle+|TRUE |+ | | | |FALSE | +|v(程序结束)/text现在，再让我们来看一下MFC的窗口是如何响应消息的。 我们先来看一段建立一个窗口的代码.cclass CMsgWnd : public CWndpublic:CMsgWnd() / ClassWizard generated virtual function overrides/AFX_VIRTUAL(CMsgWnd)virtual BOOL Create(CWnd* pParentWnd);/AFX_VIRTUAL virtual CMsgWnd() protected:/AFX_MSG(CMsgWnd)afx_msg void OnPaint();afx_msg void OnLButtonDown(UINT nFlags, CPoint point);/AFX_MSGDECLARE_MESSAGE_MAP(); BEGIN_MESSAGE_MAP(CMsgWnd, CWnd)/AFX_MSG_MAP(CMsgWnd)ON_WM_PAINT()ON_WM_LBUTTONDOWN()/AFX_MSG_MAPEND_MESSAGE_MAP() BOOL CMsgWnd:Create(CWnd *pParentWnd)return CWnd:Create(AfxRegisterWndClass(CS_DBLCLKS),Message Window, WS_VISIBLE|WS_CHILD, CRect(0,0,100,100),pParentWnd, 12345); void CMsgWnd:OnPaint()CPaintDC dc(this); / device context for painting dc.TextOut(0,0,hello); void CMsgWnd:OnLButtonDown(UINT nFlags, CPoint point)MessageBox(OnLButtonDown); CWnd:OnLButtonDown(nFlags, point);/c以上是一段标准的CWnd窗口类的子类实现代码.我想大家应该是可以看的懂的.注意到CMsgWnd类中有一句代码 DECLARE_MESSAGE_MAP()我们来看看这个宏是如何定义的:ctypedef void (AFX_MSG_CALL CCmdTarget:*AFX_PMSG)(void);/ 这是一个指向 CCmdTarget 类成员函数的指针类型. struct AFX_MSGMAP_ENTRY / 消息映射表之消息入口UINT nMessage; / 消息UINT nCode; / 控制码或者是 WM_NOTIFY 消息的通知码UINT nID; / 控件的ID,如果是窗口消息则为0UINT nLastID; / 如果是一个范围的消息,那么这是最后一个控件的IDUINT nSig; / 消息处理类型AFX_PMSG pfn; / 消息处理函数; struct AFX_MSGMAP / 消息映射表#ifdef _AFXDLL / 如果MFC是动态连接的,/ 就是编译时选择 Use MFC in a shared DLLconst AFX_MSGMAP* (PASCAL* pfnGetBaseMap)();#else / MFC是静态连接的,编译时选择 Use MFC in a static library.const AFX_MSGMAP* pBaseMap;#endif/ 如果MFC是动态连接的, 就用pfnGetBaseMap函数返回基类的消息映射表/ 否则 pBaseBap 指向基类的消息映射表 const AFX_MSGMAP_ENTRY* lpEntries; / 指向消息入口的指针; #ifdef _AFXDLL / 如果MFC是动态连接的#define DECLARE_MESSAGE_MAP() private: static const AFX_MSGMAP_ENTRY _messageEntries; / 消息入口protected: static AFX_DATA const AFX_MSGMAP messageMap; / 消息映射表static const AFX_MSGMAP* PASCAL _GetBaseMessageMap(); / 该函数返回基类的消息映射表virtual const AFX_MSGMAP* GetMessageMap() const; / 该函数返回当前类的消息映射表 #else / 静态连接的#define DECLARE_MESSAGE_MAP() private: static const AFX_MSGMAP_ENTRY _messageEntries; protected: static AFX_DATA const AFX_MSGMAP messageMap; virtual const AFX_MSGMAP* GetMessageMap() const; #endif/ 以上这段代码实际上是嵌入在你的类中. 在 .CPP 文件中我们看到还有这段宏,BEGIN_MESSAGE_MAP(CMsgWnd, CWnd)/AFX_MSG_MAP(CMsgWnd)ON_WM_PAINT()ON_WM_LBUTTONDOWN()/AFX_MSG_MAPEND_MESSAGE_MAP()现在我们再来看看它是被如何定义的. #ifdef _AFXDLL#define BEGIN_MESSAGE_MAP(theClass, baseClass) const AFX_MSGMAP* PASCAL theClass:_GetBaseMessageMap() return &baseClass:messageMap; / 返回基类的消息映射表const AFX_MSGMAP* theClass:GetMessageMap() const return &theClass:messageMap; / 返回当前类的消息映射表 AFX_DATADEF const AFX_MSGMAP theClass:messageMap = / 消息映射表 &theClass:_GetBaseMessageMap, &theClass:_messageEntries0 ; const AFX_MSGMAP_ENTRY theClass:_messageEntries = #else#define BEGIN_MESSAGE_MAP(theClass, baseClass) const AFX_MSGMAP* theClass:GetMessageMap() const return &theClass:messageMap; / 返回当前类的消息映射表 AFX_DATADEF const AFX_MSGMAP theClass:messageMap = / 消息映射表 &baseClass:messageMap, &theClass:_messageEntries0 ; 可以看到这是 MFC 动态连接与静态连接的区别所在 动态连接时使用函数 _GetBaseMessageMap 返回 &baseClass:messageMap而静态连接是直接使用.至于Microsoft为什么要这样做,好像没有什么很好的理由.当然这个并不重要,我们暂且不用理会. const AFX_MSGMAP_ENTRY theClass:_messageEntries = /开始初始化消息入口 #endif #define END_MESSAGE_MAP() 0, 0, 0, 0, AfxSig_end, (AFX_PMSG)0 ; 指示消息映射结束. 在这两个宏之间还有ON_WM_PAINT()ON_WM_LBUTTONDOWN()它们是我们在ClassWizard中选择了WM_PAINT和WM_LBUTTONDOWN消息后,MFC自动加入的,那么这两个又是如何定义的呢? #define ON_WM_PAINT() WM_PAINT, 0, 0, 0, AfxSig_vv, | | | | +- 消息处理类型| | | +- LastID| | +- ID=0, 窗口消息| +- 控制码+ WM_PAINT 消息(AFX_PMSG)(AFX_PMSGW)(void (AFX_MSG_CALL CWnd:*)(void)&OnPaint , 消息处理函数. #define ON_WM_LBUTTONDOWN() WM_LBUTTONDOWN, 0, 0, 0, AfxSig_vwp, WM_LBUTTON 消息(AFX_PMSG)(AFX_PMSGW)(void (AFX_MSG_CALL CWnd:*)(UINT, CPoint)&OnLButtonDown , 消息处理函数 现在我们差不多可以看得出来了,消息处理函数可以靠_messageEntries来找到每个消息的处理函数.我们可以再看看CWnd类来验证我们的想法.先看一下窗口的建立过程:BOOL CWnd:Create(LPCTSTR lpszClassName,LPCTSTR lpszWindowName, DWORD dwStyle,const RECT& rect,CWnd* pParentWnd, UINT nID,CCreateContext* pContext)/ cant use for desktop or pop-up windows (use CreateEx instead)ASSERT(pParentWnd != NULL);ASSERT(dwStyle & WS_POPUP) = 0); return CreateEx(0, lpszClassName, lpszWindowName,dwStyle | WS_CHILD,rect.left, rect.top,rect.right rect.left, rect.bottom rect.top,pParentWnd-GetSafeHwnd(), (HMENU)nID, (LPVOID)pContext); BOOL CWnd:CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,LPCTSTR lpszWindowName, DWORD dwStyle,int x, int y, int nWidth, int nHeight,HWND hWndParent, HMENU nIDorHMenu, LPVOID lpParam)/ allow modification of several common create parametersCREATESTRUCT cs;cs.dwExStyle = dwExStyle;cs.lpszClass = lpszClassName;cs.lpszName = lpszWindowName;cs.style = dwStyle;cs.x = x;cs.y = y;cs.cx = nWidth;cs.cy = nHeight;cs.hwndParent = hWndParent;cs.hMenu = nIDorHMenu;cs.hInstance = AfxGetInstanceHandle();cs.lpCreateParams = lpParam; if (!PreCreateWindow(cs)PostNcDestroy();return FALSE; AfxHookWindowCreate(this); 函数见后HWND hWnd = :CreateWindowEx(cs.dwExStyle, cs.lpszClass,cs.lpszName, cs.style, cs.x, cs.y, cs.cx, cs.cy,cs.hwndParent, cs.hMenu, cs.hInstance, cs.lpCreateParams); if (!AfxUnhookWindowCreate()PostNcDestroy(); / cleanup if CreateWindowEx fails too soon if (hWnd = NULL)return FALSE;ASSERT(hWnd = m_hWnd); / should have been set in send msg hookreturn TRUE; / for child windowsBOOL CWnd:PreCreateWindow(CREATESTRUCT& cs)if (cs.lpszClass = NULL)/ make sure the default window class is registeredif (!AfxDeferRegisterClass(AFX_WND_REG)return FALSE; / no WNDCLASS provided use child window defaultASSERT(cs.style & WS_CHILD);cs.lpszClass = _afxWnd;return TRUE; void AFXAPI AfxHookWindowCreate(CWnd* pWnd)_AFX_THREAD_STATE* pThreadState = _afxThreadState.GetData();if (pThreadState-m_pWndInit = pWnd)return; if (pThreadState-m_hHookOldCbtFilter = NULL)pThreadState-m_hHookOldCbtFilter = :SetWindowsHookEx(WH_CBT,Computer-based Training,当建立、删除、移动、最大化、最小化窗口时，将会调用钩子函数。_AfxCbtFilterHook, NULL, :GetCurrentThreadId(); 钩子函数if (pThreadState-m_hHookOldCbtFilter = NULL)AfxThrowMemoryException();ASSERT(pThreadState-m_hHookOldCbtFilter != NULL);ASSERT(pWnd != NULL);ASSERT(pWnd-m_hWnd = NULL); / only do once ASSERT(pThreadState-m_pWndInit = NULL); / hook not already in progresspThreadState-m_pWndInit = pWnd; BOOL AFXAPI AfxUnhookWindowCreate()_AFX_THREAD_STATE* pThreadState = _afxThreadState.GetData();#ifndef _AFXDLLif (afxContextIsDLL & pThreadState-m_hHookOldCbtFilter != NULL):UnhookWindowsHookEx(pThreadState-m_hHookOldCbtFilter);删除钩子函数pThreadState-m_hHookOldCbtFilter = NULL;#endifif (pThreadState-m_pWndInit != NULL)pThreadState-m_pWndInit = NULL;return FALSE; / was not successfully hookedreturn TRUE; / Window creation hooksLRESULT CALLBACK_AfxCbtFilterHook(int code, WPARAM wParam, LPARAM lParam)_AFX_THREAD_STATE* pThreadState = _afxThreadState.GetData();if (code != HCBT_CREATEWND) 是要建立窗口吗？/ wait for HCBT_CREATEWND just pass others onreturn CallNextHookEx(pThreadState-m_hHookOldCbtFilter, code,wParam, lParam); ASSERT(lParam != NULL);LPCREATESTRUCT lpcs = (LPCBT_CREATEWND)lParam)-lpcs;ASSERT(lpcs != NULL); / this hook exists to set the SendMessage hook on window creations/ (but this is only done for MFC windows or non-child windows)/ the subclassing cannot be done at this point because on Win32s/ the window does not have the WNDPROC set yetCWnd* pWndInit = pThreadState-m_pWndInit;if (pWndInit != NULL | (!(lpcs-style & WS_CHILD) & !afxContextIsDLL)ASSERT(wParam != NULL); / should be non-NULL HWNDHWND hWnd = (HWND)wParam;WNDPROC oldWndProc;if (pWndInit != NULL) 窗口建立来自一个CWnd?/ the window should not be in the permanent map at this timeASSERT(CWnd:FromHandlePermanent(hWnd) = NULL); / connect the HWND to pWndInitpWndInit-Attach(hWnd);/ allow other subclassing to occur firstpWndInit-PreSubclassWindow(); WNDPROC *pOldWndProc = pWndInit-GetSuperWndProcAddr();ASSERT(pOldWndProc != NULL); #ifndef _MAC_AFX_CTL3D_STATE* pCtl3dState;DWORD dwFlags;if (!afxData.bWin4 & !afxContextIsDLL &(pCtl3dState = _afxCtl3dState.GetDataNA() != NULL &pCtl3dState-m_pfnSubclassDlgEx != NULL &(dwFlags = AfxCallWndProc(pWndInit, hWnd, WM_QUERY3DCONTROLS) != 0) / was the class registered with AfxWndProc?WNDPROC afxWndProc = AfxGetAfxWndProc();函数见后BOOL bAfxWndProc = (WNDPROC)GetWindowLong(hWnd, GWL_WNDPROC) = afxWndProc); pCtl3dState-m_pfnSubclassDlgEx(hWnd, dwFlags); / subclass the window if not already wired to AfxWndProcif (!bAfxWndProc)/ subclass the window with standard AfxWndProcoldWndProc = (WNDPROC)SetWindowLong(hWnd, GWL_WNDPROC,(DWORD)afxWndProc); / 修改窗口的WndProc! ASSERT(oldWndProc != NULL);*pOldWndProc = oldWndProc;else#endif/ subclass the window with standard AfxWndProcWNDPROC afxWndProc = AfxGetAfxWndProc();oldWndProc = (WNDPROC)SetWindowLong(hWnd, GWL_WNDPROC,(DWORD)afxWndProc);ASSERT(oldWndProc != NULL);if (oldWndProc != afxWndProc)*pOldWndProc = oldWndProc;pThreadState-m_pWndInit = NULL;elseASSERT(!afxContextIsDLL); / should never get here / subclass the window with the proc which does gray backgroundsoldWndProc = (WNDPROC)GetWindowLong(hWnd, GWL_WNDPROC);if (oldWndProc != NULL)ASSERT(GetProp(hWnd, szAfxOldWndProc) = NULL);SetProp(hWnd, szAfxOldWndProc, oldWndProc);if (WNDPROC)GetProp(hWnd, szAfxOldWndProc) = oldWndProc)SetWindowLong(hWnd, GWL_WNDPROC,(DWORD)(pThreadState-m_bDlgCreate ?_AfxGrayBackgroundWndProc : _AfxActivationWndProc);ASSERT(oldWndProc != NULL); LRESULT lResult = CallNextHookEx(pThreadState-m_hHookOldCbtFilter, code,wParam, lParam); #ifndef _AFXDLLif (afxContextIsDLL):UnhookWindowsHookEx(pThreadState-m_hHookOldCbtFilter);pThreadState-m_hHookOldCbtFilter = NULL;#endifreturn lResult; / always indirectly accessed via AfxGetAfxWndProcWNDPROC AFXAPI AfxGetAfxWndProc()#ifdef _AFXDLLreturn AfxGetModuleState()-m_pfnAfxWndProc;/ 如果MFC是动态连入，返回的地址是AfxWndProcBase#elsereturn &AfxWndProc; / 否则返回AfxWndProc#endif / The WndProc for all CWnds and derived classes LRESULT CALLBACKAfxWndProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)/ special message which identifies the window as using AfxWndProcif (nMsg = WM_QUERYAFXWNDPROC) 查询是否为AFX的窗口过程return 1; / all other messages route through message mapCWnd* pWnd = CWnd:FromHandlePermanent(hWnd);FromHandlePermanent函数用于返回一个和hWnd句柄对应的永久的CWnd类，所谓永久的，就是CWnd调用了Attach函数连上了一个窗口句柄。 ASSERT(pWnd != NULL);ASSERT(pWnd-m_hWnd = hWnd);return AfxCallWndProc(pWnd, hWnd, nMsg, wParam, lParam); 函数见后 #ifdef _AFXDLL#undef AfxWndProcLRESULT CALLBACKAfxWndProcBase(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)AFX_MANAGE_STATE(_afxBaseModuleState.GetData();/ 由于MFC是动态连入的，所以必须要这条语句！return AfxWndProc(hWnd, nMsg, wParam, lParam);调用MFC静态连入时使用的函数#endif / 微软官方规定的发送消息给CWnd的函数LRESULT AFXAPI AfxCallWndProc(CWnd* pWnd, HWND hWnd, UINT nMsg,WPARAM wParam = 0, LPARAM lParam = 0)_AFX_THREAD_STATE* pThreadState = _afxThreadState.GetData();MSG oldState = pThreadState-m_lastSentMsg; / save for nestingpThreadState-m_lastSentMsg.hwnd = hWnd;pThreadState-m_lastSentMsg.message = nMsg;pThreadState-m_lastSentMsg.wParam = wParam;pThreadState-m_lastSentMsg.lParam = lParam; #ifdef _DEBUGif (afxTraceFlags & traceWinMsg)_AfxTraceMsg(_T(WndProc), &pThreadState-m_lastSentMsg);#endif / Catch exceptions thrown outside the scope of a callback/ in debug builds and warn the user.LRESULT lResult;TRY#ifndef _AFX_NO_OCC_SUPPORT/ special case for WM_DESTROYif (nMsg = WM_DESTROY) & (pWnd-m_pCtrlCont != NULL)pWnd-m_pCtrlCont-OnUIActivate(NULL);#endif / special case for WM_INITDIALOGCRect rectOld;DWORD dwStyle;if (nMsg = WM_INITDIALOG)_AfxPreInitDialog(pWnd, &rectOld, &dwStyle); / delegate to objects WindowProclResult = pWnd-WindowProc(nMsg, wParam, lParam);调用CWnd类的WindowProc函数,函数见后 / more special case for WM_INITDIALOGif (nMsg = WM_INITDIALOG)_AfxPostInitDialog(pWnd, rectOld, dwStyle);CATCH_ALL(e)lResult = AfxGetThread()-ProcessWndProcException(e, &pThreadState-m_lastSentMsg);TRACE1(Warning: Uncaught exception in WindowProc (returning %ld).n,lResult);DELETE_EXCEPTION(e);END_CATCH_ALL pThreadState-m_lastSentMsg = oldState;return lResult;消息处理转入CWnd类了, LRESULT CWnd:WindowProc(UINT message, WPARAM wParam, LPARAM lParam) / OnWndMsg does most of the work, except for DefWindowProc callLRESULT lResult = 0;if (!OnWndMsg(message, wParam, lParam, &lResult)处理窗口消息 lResult = DefWindowProc(message, wParam, lParam);如果没有处理，就调用DefWindowProc，呵呵，和我们以前用C写Windows程序一样！return lResult; BOOL CWnd:OnWndMsg(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pResult)LRESULT lResult = 0; / special case for commandsif (message = WM_COMMAND) WM_COMMAND消息？if (OnCommand(wParam, lParam) 调用OnCommand函数，这是一个虚函数lResult = 1;goto LReturnTrue;return FALSE; / special case for notifiesif (message = WM_NOTIFY) 通告消息？NMHDR* pNMHDR = (NMHDR*)lParam;if (pNMHDR-hwndFrom != NULL &OnNotify(wParam, lParam, &lResult)调用OnNotify函数，也是一个虚函数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; const AFX_MSGMAP* pMessageMap; pMessageMap = GetMessageMap(