WTL-一个用于简化WTL应用程序创建工作的类

手动编写WTL程序的入口点代码比较繁琐，将其封装成一个应用程序类之后可简化很多：

template<typename T, typename TMainWindow, bool bInitializeCom = true>
class CWTLApplicationT :
    public CAppModule
{
public:
    //Call this method in the application's entry point(_tWinMain(),ect...)
    int WinMain(HINSTANCE hInstance,LPTSTR lpCmdLine,int nCmdShow)
    {
        UNREFERENCED_PARAMETER(lpCmdLine);
        T* pT = static_cast<T*>(this);
        pT->OnStartup();
        HRESULT hr = S_OK;
        if (bInitializeCom)
        {
            hr = ::CoInitialize(NULL);
            // If you are running on NT 4.0 or higher you can use the following 
            // call instead to make the EXE free threaded. This means that calls 
            // come in on a random RPC thread.
            //  hr = ::CoInitializeEx(NULL, COINIT_MULTITHREADED);
            CHECKHR(hr);
        }
        // This resolves ATL window thunking problem when Microsoft Layer 
        // for Unicode (MSLU) is used
        ::DefWindowProc(NULL, 0, 0, 0L);
        
        pT->OnInitCommonControl();
        hr = Init(NULL, hInstance);
        CHECKHR(hr);
        int nRet = 0;
        {
            CMessageLoop msgLoop;
            AddMessageLoop(&msgLoop);
            TMainWindow wndMain;
            if(wndMain.Create(NULL,CWindow::rcDefault) == NULL)
            {
                ATLTRACE(_T("Failed to create Main window!\n"));
                return 0;
            }
            wndMain.ShowWindow(nCmdShow);
            wndMain.UpdateWindow();
            nRet = msgLoop.Run();
            RemoveMessageLoop();
        }
        Term();
        if (bInitializeCom)
            ::CoUninitialize();
        pT->OnShutdown();
        return nRet;
    }
protected:
    //Overridable methods
    void OnStartup(){}
    void OnShutdown(){}
    void OnInitCommonControl()
    {
        // Add flags to support other controls
        AtlInitCommonControls(ICC_COOL_CLASSES|ICC_BAR_CLASSES|ICC_WIN95_CLASSES);
    }
};
template<typename TMainWindow, bool bInitializeCom = true>
class CWTLApplication :
    public CWTLApplicationT<CWTLApplication<TMainWindow,bInitializeCom>, TMainWindow, bInitializeCom>
{
};

使用方法：

1.如果需要修改CWTLApplicationT的功能，可从CWTLApplicationT派生自己的新类，覆盖OnStartup()等函数，以添加自定义功能：

class CMainApp :
    public CWTLApplicationT<CMainApp,CMainWindow,false>
{
public:
    void OnStartup()
    {
        //Do some work when starting up...
    }
    void OnShutdown()
    {
        //Do some work when shuting down...
    }
};
CMainApp g_MainApp;

2.如果不需要修改CWTLApplicationT提供的功能，可直接使用typedef来定义一个新类：

typedef CWTLApplication<CMainWindow,false> CMainApp;
CMainApp g_MainApp;

3.定义完毕后，添加_tWinMain()入口函数：

int WINAPI _tWinMain(HINSTANCE hInstance,HINSTANCE,LPTSTR lpCmdLine,int nCmdShow)
{
    g_MainApp.WinMain(hInstance,lpCmdLine,nCmdShow);
}