如何在UWP中更改RichTextBlock的右键菜单

<Page.Resources>
    <ContextMenu x:Key="CustomContextMenu">
        <MenuFlyout>
            <MenuFlyoutItem Text="复制" Click="Copy_Click"/>
            <MenuFlyoutItem Text="粘贴" Click="Paste_Click"/>
            <!-- 添加其他菜单项 -->
        </MenuFlyout>
    </ContextMenu>
</Page.Resources>

<RichTextBlock ContextMenu="{StaticResource CustomContextMenu}">
    <!-- RichTextBlock的内容 -->
</RichTextBlock>

private void Copy_Click(object sender, RoutedEventArgs e)
{
    // 执行复制操作的代码
}

private void Paste_Click(object sender, RoutedEventArgs e)
{
    // 执行粘贴操作的代码
}