进程唯一示例化的实现，利用对话框标题来实现。

// MainFrm.cpp : implmentation of the CMainFrame class // ///////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "resource.h" #include "aboutdlg.h" #include "testUniquleInstanceView.h" #include "MainFrm.h" BOOL CMainFrame::PreTranslateMessage(MSG* pMsg) { if(CFrameWindowImpl<CMainFrame>::PreTranslateMessage(pMsg)) return TRUE; return m_view.PreTranslateMessage(pMsg); } BOOL CMainFrame::OnIdle() { return FALSE; } LRESULT CMainFrame::OnCreate(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/) { CreateSimpleCEMenuBar(IDR_MAINFRAME, SHCMBF_HMENU); m_hWndClient = m_view.Create(m_hWnd); // register object for message filtering and idle updates CMessageLoop* pLoop = _Module.GetMessageLoop(); ATLASSERT(pLoop != NULL); pLoop->AddMessageFilter(this); pLoop->AddIdleHandler(this); return 0; } LRESULT CMainFrame::OnFileExit(WORD /*wNotifyCode*/, WORD /*wID*/, HWND /*hWndCtl*/, BOOL& /*bHandled*/) { PostMessage(WM_CLOSE); return 0; } LRESULT CMainFrame::OnFileNew(WORD /*wNotifyCode*/, WORD /*wID*/, HWND /*hWndCtl*/, BOOL& /*bHandled*/) { // TODO: add code to initialize document return 0; } LRESULT CMainFrame::OnAppAbout(WORD /*wNotifyCode*/, WORD /*wID*/, HWND /*hWndCtl*/, BOOL& /*bHandled*/) { CAboutDlg dlg; dlg.DoModal(); return 0; } HRESULT CMainFrame::ActivatePreviousInstance(HINSTANCE hInstance) { CFrameWndClassInfo& classInfo = CMainFrame::GetWndClassInfo(); int nRet = ::LoadString(hInstance, IDR_MAINFRAME, classInfo.m_szAutoName, sizeof(classInfo.m_szAutoName)/sizeof(classInfo.m_szAutoName[0])); ATLASSERT(0 != nRet); classInfo.m_wc.lpszClassName = classInfo.m_szAutoName; const TCHAR* pszClass = classInfo.m_wc.lpszClassName; if(NULL == pszClass || '\0' == *pszClass) { return E_FAIL; } // Orginally 500ms in SmartPhone 2003 App Wizard generated code // A lower value will result in a more responsive start-up of // the existing instance or termination of this instance. const DWORD dRetryInterval = 100; // Orginally 5 in SmartPhone 2003 App Wizard generated code // Multiplied by 5, since wait time was divided by 5. const int iMaxRetries = 25; for(int i = 0; i < iMaxRetries; ++i) { // Don't need ownership of the mutex HANDLE hMutex = CreateMutex(NULL, FALSE, pszClass); DWORD dw = GetLastError(); if(NULL == hMutex) { HRESULT hr; switch(dw) { case ERROR_INVALID_HANDLE: // A non-mutext object with this name already exists. hr = E_INVALIDARG; break; default: // This should never happen... hr = E_FAIL; } return hr; } // If the mutex already exists, then there should be another instance running if(ERROR_ALREADY_EXISTS == dw) { // Just needed the error result, in this case, so close the handle. CloseHandle(hMutex); // Try to find the other instance, don't need to close HWND's. // Don't check title in case it is changed by app after init. HWND hwnd = FindWindow(pszClass, NULL); if(NULL == hwnd) { // It's possible that the other istance is in the process of starting up or shutting down. // So wait a bit and try again. Sleep(dRetryInterval); continue; } else { // Set the previous instance as the foreground window // The "| 0x1" in the code below activates the correct owned window // of the previous instance's main window according to the SmartPhone 2003 // wizard generated code. if(0 != SetForegroundWindow(reinterpret_cast<HWND>(reinterpret_cast<ULONG>(hwnd) | 0x1))) { // S_FALSE indicates that another instance was activated, so this instance should terminate. return S_FALSE; } } } else { // This is the first istance, so return S_OK. // Don't close the mutext handle here. // Do it on app shutdown instead. return S_OK; } } // The mutex was created by another instance, but it's window couldn't be brought // to the foreground, so ssume it's not a invalid instance (not this app, hung, etc.) // and let this one start. return S_OK; }