MFC开发常见问题的回答2

第一辑在http://www.csdn.net/develop/read_article.asp?id=6676

1.如何让我的程序运行的时候最大化？

(1)在appwizard第4步选择“advanced"从中选择Mainframe的Maximized

(2)对于MDI程序，在CWinApp::InitInstance() 中做下面改动

// Create main MDI Frame window.
CMainFrame* pMainFrame = new CMainFrame;
if (!pMainFrame->LoadFrame(IDR_MAINFRAME))
    return FALSE;

m_nCmdShow = SW_SHOWMAXIMIZED;  // 注意添加此行！！！

pMainFrame->ShowWindow(m_nCmdShow);
pMainFrame->UpdateWindow();
m_pMainWnd = pMainFrame;
(3)对于SDI程序，在CWinApp::InitInstance() 中的OnFileNew()调用之前

m_nCmdShow = SW_SHOWMAXIMIZED;
//  下面创建空文档
OnFileNew();

2,如何给其他线程发消息？

用SendNotifyMessage() 函数。


3,如何让我的程序只运行一次？

const char* MyMainWndClassName = "MyMainWndXQW"
BOOL CMyApp::InitApplication()
{
    // Call base class. Default version does nothing.
    CWinApp::InitApplication();
    WNDCLASS wndcls;
    // Start with NULL defaults.
    memset(&wndcls, 0, sizeof(WNDCLASS)); 
    // Get class information for default window class.
    ::GetClassInfo(AfxGetInstanceHandle(),"AfxFrameOrView",&wndcls);
    // Substitute unique class name for new class.
    wndcls.lpszClassName = MyMainWndClassName;
    // Register new class and return the result code.
    return ::RegisterClass(&wndcls);
}
BOOL CMyApp::FirstInstance()
{
    CWnd *PrevCWnd, *ChildCWnd;
    // Determine if another window with our class name exists.
    PrevCWnd = CWnd::FindWindow(MyMainWndClassName, NULL);
    if (PrevCWnd != NULL)
    {
        // If so, does it have any pop-ups?
        ChildCWnd=PrevCWnd->GetLastActivePopup();
        // Bring the main window to the top.
        PrevCWnd->BringWindowToTop();
        // If iconic, restore the main window.
        if (PrevCWnd->IsIconic())
            PrevCWnd->ShowWindow(SW_RESTORE);
        // If there are pop-ups, bring them along too!
        if (PrevCWnd != ChildCWnd)
            ChildCWnd->BringWindowToTop();
        // Return FALSE. This isn't the first instance
        // and we are done activating the previous one.
        return FALSE;
    }
    else
        // First instance. Proceed as normal.
        return TRUE;
}
CMyApp::InitInstance()
{
    if (!FirstInstance())
        return FALSE;
    // ...
}




4,MDI程序，关闭子窗口同时关闭父窗口，该如何做？

在子窗口的OnClose函数里添加
ASSERT(AfxGetMainWnd() != NULL);
AfxGetMainWnd()->SendMessage(WM_CLOSE);



菜单问题：

1，我在程序中用了MenuBar，结果找不到菜单了，我的方法是：
CMenu *menu;
menu = GetMenu()->GetSubMenu(0);

答：

AfxGetApp()->m_pMainWnd->GetMenu()->GetSubMenu(0);





2,如何动态修改MainFrame的菜单？

CMenu newMenu;
newMenu.LoadMenu (IDR_MENU1);
AfxGetMainWnd()->SetMenu( &newMenu );
AfxGetMainWnd()->DrawMenuBar();
newMenu.Detach ();