MFC框架分析

每个MFC程序都有一个the全局对象，此对象代表了这个应用程序，程序从这里诞生。

<wbr></wbr>

1、因theApp是全局对象，所以比winmain更早初始化。

<wbr></wbr>

2、theApp的初始化，先引发了其构造函数。因theApp派生于CWinApp，则也引发了CWinApp的构造函数

<wbr></wbr>

3、CWinApp中的几条重要的初始化代码：

AFX_MODULE_STATE* pModuleState =_AFX_CMDTARGET_GETSTATE();
AFX_MODULE_THREAD_STATE* pThreadState =pModuleState->m_thread;

pThreadState->m_pCurrentWinThread<wbr>=<wbr><strong>this</strong>;</wbr></wbr>

pModuleState->m_pCurrentWinApp<wbr>=<wbr><strong>this</strong>;</wbr></wbr>

可以看到m_pCurrentWinThread与m_pCurrentWinApp现在都指向theApp。

<wbr></wbr>

4、CWinApp初始化后，进入winmain。winmain中进行了如下调用：

return<wbr><strong>AfxWinMain</strong>(hInstance,hPrevInstance, lpCmdLine, nCmdShow);</wbr>

<wbr></wbr>

5、AfxWinMain中的重要代码：
CWinThread* pThread =AfxGetThread();//AfxGetThread其实就是取得了theApp的指针

CWinApp* pApp = AfxGetApp();//AfxGetApp其实就是取的了theApp的指针

<wbr></wbr>

AfxGetThread的定义：

CWinThread* AFXAPIAfxGetThread()

{

<wbr><wbr>AFX_MODULE_THREAD_STATE*pState = AfxGetModuleThreadState();<br><wbr> CWinThread* pThread=<wbr><strong>pState-&gt;m_pCurrentWinThread</strong>;</wbr></wbr></wbr></wbr>

<wbr></wbr>

<wbr><wbr>if(pThread == NULL)<br><wbr><wbr><wbr><wbr><wbr>pThread =<wbr><strong>AfxGetApp();</strong></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr></wbr>

<wbr>returnpThread<strong>;//pThread指向theApp</strong></wbr>

}

<wbr></wbr>

AfxGetApp的定义：

_AFXWIN_INLINE CWinApp*AFXAPI AfxGetApp()
<wbr>{ return afxCurrentWinApp; }</wbr>

<wbr></wbr>

#defineafxCurrentWinApp<wbr><wbr><wbr>AfxGetModuleState()-&gt;<strong>m_pCurrentWinApp//</strong>AfxGetApp也返回了theApp的指针。</wbr></wbr></wbr>

<wbr></wbr>

AfxWinInit(hInstance, hPrevInstance, lpCmdLine,nCmdShow);//内部的初始化操作

节选其中的一些重要代码：

// fill in the initialstate for the application
CWinApp* pApp = AfxGetApp();

if (pApp != NULL)
<wbr>{<br><wbr><wbr>// Windows specificinitialization (not done if no CWinApp)<br><wbr><wbr>pApp-&gt;m_hInstance= hInstance;<br><wbr><wbr>pApp-&gt;m_hPrevInstance= hPrevInstance;<br><wbr><wbr>pApp-&gt;m_lpCmdLine= lpCmdLine;<br><wbr><wbr>pApp-&gt;m_nCmdShow= nCmdShow;<br><wbr><wbr>pApp-&gt;SetCurrentHandles();<br><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr></wbr>

pApp->InitApplication();

这里相当于调用了theApp的InitApplication，但因大多数情况下无需改写此虚函数，所以实际调用的是CWinApp::InitApplication.其中的操作是为MFC内部管理而做，与DocumentTemplate有关。

<wbr></wbr>

pThread->InitInstance();

这里相当于调用了theApp的InitInstance，因theApp中改写了这个虚函数，所以直接调用即可。节选其中的重要代码：

<wbr></wbr>

//new一个CMultiDocTemplate对象并初始化，用来管理Doccument/view/Frame三者之间的关系

CMultiDocTemplate*pDocTemplate;
<wbr>pDocTemplate = new CMultiDocTemplate(<br><wbr><wbr>IDR_MDITYPE,<br><wbr><wbr>RUNTIME_CLASS(CMDIDoc),<br><wbr><wbr>RUNTIME_CLASS(CChildFrame), //custom MDI child frame<br><wbr><wbr>RUNTIME_CLASS(CMDIView));<br><wbr>AddDocTemplate(pDocTemplate);</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr></wbr>

//主框架窗口的初始化

CMainFrame* pMainFrame =new CMainFrame;

//LoadFrame会触发WM_CREATE消息（中间一系列调用不详述了）
<wbr>if(!pMainFrame-&gt;LoadFrame(IDR_MAINFRAME))<br><wbr><wbr>returnFALSE;</wbr></wbr></wbr>
<wbr>m_pMainWnd = pMainFrame;</wbr>

<wbr></wbr>

CMainFrame::OnCreate中，主要实现工具栏、状态栏的初始化。

<wbr></wbr>

//显示主框架窗口，并发出更新窗口

<wbr>pMainFrame-&gt;ShowWindow(m_nCmdShow);<br><wbr>pMainFrame-&gt;UpdateWindow();</wbr></wbr>

<wbr></wbr>

pThread->Run();

这里相当于调用了theApp的Run，但是theApp通常不会改写这个虚函数，所以实际调用的是CWinApp的Run。节选一些代码：

intCWinApp::Run()

<wbr><wbr><wbr>return CWinThread::Run();</wbr></wbr></wbr>

<wbr></wbr>

intCWinThread::Run()

{

<wbr><wbr>do<br><wbr><wbr>{<br><wbr><wbr><wbr><wbr>if(!PumpMessage())<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr>returnExitInstance();<strong>//收到WM_QUIT消息</strong></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr>if(IsIdleMessage(&amp;m_msgCur))<br><wbr><wbr><wbr> {<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>bIdle = TRUE;<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>lIdleCount = 0;<br><wbr><wbr><wbr> }</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr>}while (::PeekMessage(&amp;m_msgCur, NULL, NULL, NULL,PM_NOREMOVE));</wbr></wbr>

}

<wbr></wbr>

BOOLCWinThread::PumpMessage()

{

<wbr><wbr><wbr><wbr>if (!::GetMessage(&amp;m_msgCur, NULL, NULL,NULL))</wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>return FALSE<strong>;//如取得的消息是WM_QUIT,则返回FALSE</strong></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr></wbr>

<wbr><wbr><wbr><wbr><wbr>if (m_msgCur.message != WM_KICKIDLE&amp;&amp;!PreTranslateMessage(&amp;m_msgCur))<br><wbr><wbr><wbr><wbr><wbr>{<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>::TranslateMessage(&amp;m_msgCur);<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>::DispatchMessage(&amp;m_msgCur);<br><wbr><wbr><wbr><wbr><wbr>}<br><wbr><wbr><wbr><wbr><wbr><wbr>returnTRUE;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

}