MFC 解密（1） 窗口初始化过程

1. 对于Dialog程序

 

每个自己的MFC程序都有一个派生自CWinApp的类(CMyApp) 和 一个该类的全局对象 CMyApp theApp;

 

CMyApp -> CWinApp -> CWinThread -> CCmdTarget -> CObject

 

以下摘自 winmain.cpp

int AFXAPI AfxWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,_In_ LPTSTR lpCmdLine, int nCmdShow){// ...CWinThread* pThread = AfxGetThread();CWinApp* pApp = AfxGetApp();// ...if (!pThread->InitInstance()){if (pThread->m_pMainWnd != NULL){TRACE(traceAppMsg, 0, "Warning: Destroying non-NULL m_pMainWnd/n");pThread->m_pMainWnd->DestroyWindow();}nReturnCode = pThread->ExitInstance();goto InitFailure;}//...}

 

由上可见pThread->InitInstance()

CMyApp::InitInstance() 被调用

在这个函数中 窗口被

1. 创建

2. 显示

 

以下代码摘自CMyApp.cpp

BOOL CMyApp::InitInstance(){ // ... CWinApp::InitInstance(); //... CMyDlg dlg; m_pMainWnd = &dlg; INT_PTR nResponse = dlg.DoModal(); if (nResponse == IDOK) {// TODO: Place code here to handle when the dialog is// dismissed with OK } else if (nResponse == IDCANCEL) { // TODO: Place code here to handle when the dialog is// dismissed with Cancel }}

 

其中CMYDlg dlg 在基类的构造函数中设置窗体的style

在DoModal中创建并显示窗体

 

 

在DoModal中进入消息循环

对于Modal window 在CWnd::RunModalLoop() 函数用来进行消息循环

不需要调用CWinApp::Run();

 

这样一个dialog的

创建

显示

消息循环

的过程就很清楚了 

 

 

2. 对于文档程序  基本原理相同

 

以下代码摘自MyDoc.cpp

BOOL CMyDocApp::InitInstance(){ // ... CWinAppEx::InitInstance(); // ... // The one and only window has been initialized, so show and update it m_pMainWnd->ShowWindow(SW_SHOW); m_pMainWnd->UpdateWindow(); // ...}

 

程序不会被中断

在CWinApp::Run中进行消息循环

 

以下摘自winmain.cpp

int AFXAPI AfxWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,_In_ LPTSTR lpCmdLine, int nCmdShow){ // Perform specific initializationsif (!pThread->InitInstance()){if (pThread->m_pMainWnd != NULL){TRACE(traceAppMsg, 0, "Warning: Destroying non-NULL m_pMainWnd/n");pThread->m_pMainWnd->DestroyWindow();}nReturnCode = pThread->ExitInstance();goto InitFailure;}nReturnCode = pThread->Run();}