MenuItem可見性綁定的ContextMenu

Question

我需要爲菜單項創建一個上下文菜單。上下文菜單的可見性綁定到ViewModel。

當屬性更改爲true時，使用MVVM Light，即使沒有右鍵單擊菜單項，UI上也會出現上下文菜單。當值爲false時，我可以做些什麼來隱藏上下文菜單，並且只有在右鍵單擊時才能看到它？

private Boolean _IsEditable; 
public Boolean IsEditable 
{ 
    get { return _IsEditable; } 
    set 
    { 
     if (_IsEditable == value) return; 
     _IsEditable = value; 
     RaisePropertyChanged("IsEditable"); 
    } 
} 

<Menu DockPanel.Dock="Top"> 
    <MenuItem Header="{Binding Menu.Business}" Visibility="{Binding allowUI, Converter={StaticResource BoolToVisConverter} }"> 
     <MenuItem.ContextMenu> 
     <ContextMenu Visibility="{Binding Menu.IsEditable, Converter={StaticResource BoolToVisConverter} }"> 
      <MenuItem> 
       <MenuItem.Header> 
        <TextBox Text="{Binding Menu.Business, UpdateSourceTrigger=PropertyChanged}" LostFocus="end_change_UI" /> 
       </MenuItem.Header> 
      </MenuItem> 

     </ContextMenu> 
     </MenuItem.ContextMenu> 
    </MenuItem> 
</Menu> 

Answer 1

你可以申請一個Style到MenuItem只設置當IsEditable源屬性設置爲true的ContextMenu屬性：

<Menu DockPanel.Dock="Top"> 
    <MenuItem Header="{Binding Menu.Business}" Visibility="{Binding allowUI, Converter={StaticResource BoolToVisConverter} }"> 
     <MenuItem.Style> 
      <Style TargetType="MenuItem" BasedOn="{StaticResource {x:Type MenuItem}}"> 
       <Style.Triggers> 
        <DataTrigger Binding="{Binding Menu.IsEditable}" Value="True"> 
         <Setter Property="ContextMenu"> 
          <Setter.Value> 
           <ContextMenu> 
            <MenuItem> 
             <MenuItem.Header> 
              <TextBox Text="{Binding Menu.Business, UpdateSourceTrigger=PropertyChanged}" LostFocus="end_change_UI" /> 
             </MenuItem.Header> 
            </MenuItem> 
           </ContextMenu> 
          </Setter.Value> 
         </Setter> 
        </DataTrigger> 
       </Style.Triggers> 
      </Style> 
     </MenuItem.Style> 
    </MenuItem> 
</Menu>