MFC - 选中/取消选中菜单项

Question

我正在制作一个 MFC 应用程序，其中有两个菜单选项对应于两个工具栏 - 菜单选项切换工具栏的可见性。如果工具栏当前可见，我需要检查菜单选项。到目前为止，这是我所得到的：

BEGIN_MESSAGE_MAP(CLevelPackEditApp, CWinAppEx)
    // Standard file based document commands
    ON_UPDATE_COMMAND_UI(ID_LEVEL_PROPERTIES, &CLevelPackEditApp::OnViewLevelProperties)
END_MESSAGE_MAP()

void CLevelPackEditApp::OnViewLevelProperties(CCmdUI* pCmdUI)
{
    // Get a handle to the main window
    CMainFrame* main = ((CMainFrame*)m_pMainWnd);

    // Get a handle to the level properties toolbar for the main window
    CLevelProperties* obj = main->GetLevelProperties();

    if (obj->IsWindowVisible())
    {
        pCmdUI->SetCheck(0);
        obj->ShowPane(false, false, false);
    } else {
        pCmdUI->SetCheck();
        obj->ShowPane(true, false, true);
    }
}

它有效....有点。它在选中和未选中之间切换，但它每秒会多次切换 - 我怀疑检查菜单项会导致菜单更新，所以它没有选中，所以它更新，所以它被选中，aaaannnd 重复。我该如何解决这个问题？

Answer 1

ON_UPDATE_COMMAND_UI() 函数应该只设置/清除复选标记；仅在单击按钮时调用obj->ShowPane()：

BEGIN_MESSAGE_MAP(CLevelPackEditApp, CWinAppEx)
    // Standard file based document commands
    ON_COMMAND_UI(ID_LEVEL_PROPERTIES, &CLevelPackEditApp::OnViewLevelProperties)
    ON_UPDATE_COMMAND_UI(ID_LEVEL_PROPERTIES, &CLevelPackEditApp::OnUpdateViewLevelProperties)
END_MESSAGE_MAP()

void CLevelPackEditApp::OnViewLevelProperties()
{
    // Get a handle to the main window
    CMainFrame* main = ((CMainFrame*)m_pMainWnd);

    // Get a handle to the level properties toolbar for the main window
    CLevelProperties* obj = main->GetLevelProperties();

    if (obj->IsWindowVisible())
        obj->ShowPane(false, false, false);
    else
        obj->ShowPane(true, false, true);
}

void CLevelPackEditApp::OnUpdateViewLevelProperties(CCmdUI* pCmdUI)
{
    // Get a handle to the main window
    CMainFrame* main = ((CMainFrame*)m_pMainWnd);

    // Get a handle to the level properties toolbar for the main window
    CLevelProperties* obj = main->GetLevelProperties();

    pCmdUI->SetCheck(obj->IsWindowVisible());
}