让 APP 发送和处理自定义消息

1，自定消息；由于 app 不是继承与窗口类，所以不能向窗口那样 send 或 post message；

2，可以直接在 app 中 post thread message，例如这里的 WM_APP1；也可以从窗口中 post WM_COMMAND，例如这里的 WM_APP2;

2，防止 thread message 丢失，下面这个例子中，WM_APP2在主窗口创建后被post，处理函数弹出一个dialog，这时如果不显示滴用PeekMessage，thread message就被发到了窗口线程里，就丢失了。参考：

 

#define WM_APP1 (WM_APP+1) #define WM_APP2 (WM_APP+2)

BEGIN_MESSAGE_MAP(CProgramApp, CWinApp) (WM_APP1, &CProgramApp::OnHandleApp1) (WM_APP2, &CProgramApp::OnHandleApp2)     ON_COMMAND(ID_APP_ABOUT, &CProgramApp::OnAppAbout) // Standard file based document commands     ON_COMMAND(ID_FILE_NEW, &CWinApp::OnFileNew)     ON_COMMAND(ID_FILE_OPEN, &CWinApp::OnFileOpen) END_MESSAGE_MAP()

BOOL CProgramApp::InitInstance() {
       ... // Dispatch commands specified on the command line.  Will return FALSE if // app was launched with /RegServer, /Register, /Unregserver or /Unregister. if (!ProcessShellCommand(cmdInfo)) return FALSE; // The main window has been initialized, so show and update it     pMainFrame->ShowWindow(m_nCmdShow);     pMainFrame->UpdateWindow(); // // WM_APP2 was posted after main window created, need dispatch all those msg, // then post the thread msg, otherwise, the thread message lost. //     MSG Msg; while(PeekMessage(&Msg, NULL, 0, 0, PM_REMOVE))     {
           TranslateMessage(&Msg);         DispatchMessage(&Msg);     } this->PostThreadMessage(WM_APP1, 0, 0); return TRUE; } void CProgramApp::OnHandleApp1(WPARAM wParam, LPARAM lParam) {
       AfxMessageBox(_T("WM_APP1 handler")); } void CProgramApp::OnHandleApp2() {
       AfxMessageBox(_T("WM_APP2 handler")); }

int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct) {
   if (CMDIFrameWnd::OnCreate(lpCreateStruct) == -1) return -1; if (!m_wndStatusBar.Create(this))     {
           TRACE0("Failed to create status bar\n"); return -1;      // fail to create     }     m_wndStatusBar.SetIndicators(indicators, sizeof(indicators)/sizeof(UINT)); // this->PostMessage(WM_COMMAND, WM_APP2, 0); return 0; }

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