1. 主要创建主窗口或父窗口
    BOOL CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
        LPCTSTR lpszWindowName, DWORD dwStyle,
        int x, int y, int nWidth, int nHeight,
        HWND hWndParent, HMENU nIDorHMenu, LPVOID lpParam = NULL);
    2. 主要创建子窗口
    BOOL CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
        LPCTSTR lpszWindowName, DWORD dwStyle,
        const RECT& rect,
        CWnd* pParentWnd, UINT nID,
        LPVOID lpParam = NULL);

BOOL CtestDialogApp::InitInstance()
{
     //自己用 CreateEx() 创建主窗口,需要自己注册窗口类
    CWnd* pWnd = new CWnd();//要想接收消息，则需要新建一个类继承 CWnd，像 CMyMainWnd
    //CWnd* pWnd = new CMyMainWnd();
    WNDCLASS wc = { 0 };
    wc.style = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;
    wc.lpfnWndProc = ::DefWindowProc;
    wc.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
    wc.hCursor = (HCURSOR)::LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW));//加载系统的标准的光标
    //wc.hIcon=...
    wc.lpszMenuName = MAKEINTRESOURCE(IDR_MENU1);// 也可以用 (LPCTSTR)IDR_MENU1;
    wc.lpszClassName = _T("myWindow");
    RegisterClass(&wc);

    m_pMainWnd = pWnd; // 必不可少
    pWnd->CreateEx(0, wc.lpszClassName, _T("xxx窗口名"), WS_VISIBLE|WS_OVERLAPPEDWINDOW, 20, 20, 600, 400, NULL, NULL);
    return TRUE; // 必不可少
}