綁定命令到MenuItem

Question

我有ListView，我試圖將命令綁定到ListView的ContextMenu。

<ListView x:Name="listView1" ItemsSource="{Binding Path=Persons}"> 
      <ListView.Resources> 
       <ContextMenu x:Key="ItemContextMenu"> 
        <MenuItem Header="Add" /> 
        <MenuItem Header="Edit"/> 
        <Separator/> 
        <MenuItem Header="Delete" Command="{Binding Msg}" /> 
       </ContextMenu> 
      </ListView.Resources> 
      <ListView.ItemContainerStyle> 
       <Style TargetType="ListViewItem"> 
        <!--<EventSetter Event="PreviewMouseLeftButtonDown" />--><!--Handler="OnListViewItem_PreviewMouseLeftButtonDown" />--> 
        <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}"/> 
        <Setter Property="HorizontalContentAlignment" Value="Stretch" /> 
       </Style> 
      </ListView.ItemContainerStyle> 
      <ListView.View> 
       <GridView> 
        <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Path=Name}" /> 
        <GridViewColumn Header="Sur Name" DisplayMemberBinding="{Binding Path=SurName}" /> 
        <GridViewColumn Header="Age" DisplayMemberBinding="{Binding Path=Age}" /> 
       </GridView> 
      </ListView.View> 


     </ListView> 
     <Button Content="Message" Command="{Binding Msg}" /> 

綁定到按鈕效果很好，但當我點擊刪除ContextMenu中的項目，命令不工作！爲什麼？

Answer 1

您的問題與在資源中使用綁定有關。除非您使用類似{Binding Path=Value,Source={x:Static Some.StaticProperty}}的東西，否則他們通常不會工作。爲了使ElementName或DataContext綁定起作用，您需要求助於ElementSpy和DataContextSpy。在您的特定情況下，如果你是靠DataContext結合，你的XAML應該是這樣的：

 <ListView.Resources> 
      <DataContextSpy x:Name="spy" /> 
      <ContextMenu x:Key="ItemContextMenu"> 
       <MenuItem Header="Add" /> 
       <MenuItem Header="Edit"/> 
       <Separator/> 
       <MenuItem Header="Delete" Command="{Binding DataContext.Msg,Source={StaticResource spy}}" /> 
      </ContextMenu> 
     </ListView.Resources>