WPF上下文菜单“单击事件”在一个位置起作用,而不是在另一个位置起作用

我有以下XAML,它生成一个列表框,其中每个项在扩展器中包含另一个列表框,并且我已经定义了 PageContextMenu 作为顶级列表的上下文菜单 FrameContextMenu 对于较低级别的列表。

问题:两者都显示正确,但单击事件仅在顶层上下文菜单上工作,而不是在底层上下文菜单上工作。例如,单击 Delete Selected 在里面 页面上下文菜单 正确调用关联的处理程序,但单击 Delete Selected Frame(s) 在里面 框架上下文菜单 不激发关联的处理程序。我没有看到任何错误的迹象,即使我在 ContextDeleteFrames_Click 它不会被击中。就好像根本没有与该菜单项相关联的处理程序。

我看过其他一些与上下文菜单不起作用有关的问题,但似乎都不适用。嵌套的两个列表框有问题吗?

XAML:

<ListBox Name="PageListBox" ItemsSource="{Binding CurrentPack.Pages}" HorizontalAlignment="Stretch" SelectionMode="Extended">
<ListBox.Resources>
    <ContextMenu x:Key="PageContextMenu">
        <MenuItem Header="_Add" Name="ContextAddAddPage"/>
        <MenuItem Header="_Edit" Name="ContextEditPage"/>
        <MenuItem Header="_Delete Selected" Name="ContextDeletePage" Click="ContextDeletePage_Click"/>
    </ContextMenu>
    <Style TargetType="{x:Type ListBoxItem}">
        <Setter Property="ContextMenu" Value="{StaticResource PageContextMenu}"/>
        <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
        <Setter Property="HorizontalAlignment" Value="Stretch"/>
    </Style>
</ListBox.Resources>
<ListBox.ItemTemplate>
    <DataTemplate >
        <Border  BorderThickness="2" BorderBrush="White" HorizontalAlignment="Stretch">
            <StackPanel HorizontalAlignment="Stretch">
                <Label Content="{Binding PresentationName}"/>
                <Expander  VerticalAlignment="Top" HorizontalAlignment="Stretch">
                    <Expander.Header>
                        <Label Content="{Binding FrameStatusText}"/>
                    </Expander.Header>
                    <ListBox Name="FrameListBox" ItemsSource="{Binding Frames}" HorizontalAlignment="Stretch" SelectionMode="Extended">
                        <ListBox.Resources>
                            <ContextMenu x:Key="FrameContextMenu">
                                <MenuItem Header="_Add Frame" Name="ContextAddFrame"/>
                                <MenuItem Header="_Edit Frame" Name="ContextEditFrame"/>
                                <MenuItem Header="_Delete Selected Frame(s)" Name="ContextDeleteFrames" Click="ContextDeleteFrames_Click"/>
                                <MenuItem Header="Show _Preview" Name="ContextShowPreview" Click="ContextShowPreview_Click"/>
                            </ContextMenu>
                            <Style TargetType="{x:Type ListBoxItem}">
                                <Setter Property="ContextMenu" Value="{StaticResource FrameContextMenu}"/>
                                <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
                            </Style>
                        </ListBox.Resources>
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <Label Content="{Binding PresentationName}"/>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>
                </Expander>
            </StackPanel>
        </Border>
    </DataTemplate>
</ListBox.ItemTemplate>

代码隐藏:

    private void ContextDeletePage_Click(object sender, RoutedEventArgs e)
    { //this works
        Workspace.Content.DeleteSelectedPages();
    }

    private void ContextDeleteFrames_Click(object sender, RoutedEventArgs e)
    { //this doesn't!
        Workspace.Content.DeleteSelectedFrames();
    }