WPF：如何在运行时向菜单添加新的menuitem？

Question

我有一个带菜单的简单WPF应用程序。我需要在运行时动态添加菜单项。当我只是创建一个新的菜单项，并将其添加到其父MenuItem时，无论是否调用UpdateLayout，它都不会显示在菜单中。

允许菜单在运行时动态添加其他项目必须发生什么？

注意：以下代码不起作用。

            MenuItem mi = new MenuItem();
            mi.Header = "Item to add";
            mi.Visibility = Visibility.Visible;
            //addTest is a menuitem that exists in the forms defined menu
            addTest.Items.Add(mi);
            addTest.UpdateLayout();

目前，默认菜单项在xaml文件中定义。我想在此菜单及其现有菜单项中添加其他菜单项。但是，如上所述，上述代码什么都不做。

Answer 1

//Add to main menu
MenuItem newMenuItem1 = new MenuItem();
newMenuItem1.Header = "Test 123";
this.MainMenu.Items.Add(newMenuItem1);

//Add to a sub item
MenuItem newMenuItem2 = new MenuItem();
MenuItem newExistMenuItem = (MenuItem)this.MainMenu.Items[0];
newMenuItem2.Header = "Test 456";
newExistMenuItem.Items.Add(newMenuItem2);

Answer 2

我已成功将菜单项添加到预定义的菜单项。在下面的代码中，LanguageMenu在xaml的设计视图中定义，然后在C＃中添加子项。

XAML：

<MenuItem Name="LanguageMenu" Header="_Language">
  <MenuItem Header="English" IsCheckable="True" Click="File_Language_Click"/>
</MenuItem>

C＃：

// Clear the existing item(s) (this will actually remove the "English" element defined in XAML)
LanguageMenu.Items.Clear(); 

// Dynamically get flag images from a specified folder to use for definingthe menu items 
string[] files = Directory.GetFiles(Settings.LanguagePath, "*.png");
foreach (string imagePath in files)
{
  // Create the new menu item
  MenuItem item = new MenuItem();

  // Set the text of the menu item to the name of the file (removing the path and extention)
  item.Header = imagePath.Replace(Settings.LanguagePath, "").Replace(".png", "").Trim("\\".ToCharArray());
  if (File.Exists(imagePath))
  {
    // Create image element to set as icon on the menu element
    Image icon = new Image();
    BitmapImage bmImage = new BitmapImage();
    bmImage.BeginInit();
    bmImage.UriSource = new Uri(imagePath, UriKind.Absolute);
    bmImage.EndInit();
    icon.Source = bmImage;
    icon.MaxWidth = 25;
    item.Icon = icon;
  }

  // Hook up the event handler (in this case the method File_Language_Click handles all these menu items)
  item.Click += new RoutedEventHandler(File_Language_Click); 

  // Add menu item as child to pre-defined menu item
  LanguageMenu.Items.Add(item); // Add menu item as child to pre-defined menu item
}

Answer 3

我遇到了同样的问题。在我的情况下，问题是在XAML中<menuitem>直接包含在<toolbar>中。一旦我把<menuitem>放在<menu>里面就开始工作了。所以：

<toolbar>
   <menuitem>
   </menuitem>
</toolbar>   

不好

<toolbar>
    <menu>
        <menuitem>
        </menuitem>
    </menu>
</toolbar>   

很好

Answer 4

我确实必须为我打算动态创建子项的现有项目提供名称。另外，我遇​​到了一个问题，我正在点击Window_Loaded事件，它在运行之后跳出了事件：

row.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));

我必须确保在运行上面的行之前加载了菜单项。

这个问题很常见的原因是因为intellisense推断Items集合是“只读”的。这个答案是部分补充，因为上面的答案似乎表明，如果您有预先存在的项目，您必须在代码中删除它们或根本没有它们。事实并非如此。我已经能够使用预先存在的项目并在代码中添加其他动态菜单项：

    <DataGrid AutoGenerateColumns="False" HorizontalAlignment="Stretch" Margin="12,29,12,12" Name="grid" VerticalAlignment="Stretch" Background="#FF3A81A0" AlternatingRowBackground="#FFD9EEF2" FontSize="15" RowHeaderWidth="0" KeyDown="grid_KeyDown">
        <DataGrid.ContextMenu>
            <ContextMenu>
                <MenuItem Header="_Encrypt Row Values" Click="MenuItem_ContextMenu_Click_EncryptRowValues" Name="MenuItem_EncryptRowValues" />
                <MenuItem Header="De_crypt Row Values" Click="MenuItem_ContextMenu_Click_DecryptRowValues" Name="MenuItem_DecryptRowValues" />
                <MenuItem Header="Copy Row_s" Click="MenuItem_ContextMenu_Click_CopyRows" />
            </ContextMenu>
        </DataGrid.ContextMenu>
        <DataGrid.Resources>


            //Add Encryption Menu Items
            for (int i=0; i< encryptionKeys.Count; i++)
            {
                MenuItem keyOption = new MenuItem();
                keyOption.Header = "_" + i.ToString() + " " + encryptionKeys[i];
                MenuItem_EncryptRowValues.Items.Add(keyOption);
            }

            //Add Decryption Menu Items
            for (int i = 0; i < encryptionKeys.Count; i++)
            {
                MenuItem keyOption = new MenuItem();
                keyOption.Header = "_" + i.ToString() + " " + encryptionKeys[i];
                MenuItem_DecryptRowValues.Items.Add(keyOption);
            }

Answer 5

ASP.NET - > WEB表单 - >创建菜单

CREATE TABLE `webmenu` (
  `idmenu` smallint(5) NOT NULL,
  `submenu` smallint(5) DEFAULT NULL,
  `menu_title` varchar(45) DEFAULT NULL,
  `menu_url` varchar(45) DEFAULT NULL,
  `status` enum('1','0') DEFAULT '1',
  PRIMARY KEY (`idmenu`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

SELECT 
idmenu,
(select menu_title from webmenu where idmenu=wm.submenu and status='1') as childmenu,
menu_title,
menu_url 
FROM tartyp.webmenu as wm
where
status='1'
order by idmenu, submenu;

---

        cmd = new MySql.Data.MySqlClient.MySqlCommand(queryStr, conn);

        reader = cmd.ExecuteReader();
        MainMenu.Items.Clear();
        while (reader.Read())
        {

            if (reader["childmenu"] == DBNull.Value)
            {
                MenuItem homeMenuItem = new MenuItem(reader["menu_title"].ToString(), reader["menu_url"].ToString());
                MainMenu.Items.Add(homeMenuItem);
            }
            else
            {
                String childmenu = reader["childmenu"].ToString();                    

                for (int i = 0; i < MainMenu.Items.Count; i++)
                {
                    if (MainMenu.Items[i].Text == childmenu)
                    {                                                       
                        MenuItem childMenuItem = new MenuItem(reader["menu_title"].ToString(), reader["menu_url"].ToString());
                        MenuItem findMenuItem = MainMenu.Items[i];
                        findMenuItem.ChildItems.Add(childMenuItem);
                        break;    
                    }
                }
            }

        }
        reader.Close();
        conn.Close();