ContextMenu选择旧项目

Question

所以基本上就是这种情况。我有一个longlistselector显示的数据（比如，汽车的列表）：

<phone:LongListSelector x:Name="list" ItemsSource="{Binding CarList}"> 
         <phone:LongListSelector.ItemTemplate> 
          <DataTemplate> 
           <StackPanel> 
             <toolkit:ContextMenuService.ContextMenu> 
             <toolkit:ContextMenu> 
              <toolkit:MenuItem Click="DeleteMenuItem_Click" Header="delete"/> 
             </toolkit:ContextMenu> 
            </toolkit:ContextMenuService.ContextMenu> 
            <TextBlock Text="{Binding SomeText}"> 
           </StackPanel> 
          </DataTemplate> 
         </phone:LongListSelector.ItemTemplate> 
</phone:LongListSelector> 

然后，我这是怎么处理的缺失：

private void DeleteMenuItem_Click(object sender, RoutedEventArgs e) 
     { 
      Car data = (sender as MenuItem).DataContext as Car; 


       using (var db = new SQLiteConnection(App.DBpath)) 
       { 
        var existing = db.Query<Feed>("select * from Cars where Id = " + data.Id.ToString()).FirstOrDefault(); 

        if (existing != null) 
        { 

         db.RunInTransaction(() => 
         { 
          db.Delete(existing); 

         }); 
         App.ViewModel.loadCarData(); 
        } 
       } 
     } 

现在的问题是，在删除一些之后，上下文菜单开始给旧选择，并且不会更新，这使得var existing = db.Query<Feed>("select * from Cars where Id = " + data.Id.ToString()).FirstOrDefault();显然返回null，因为它已经从数据库中删除。任何想法如何解决这个问题？

Answer 1

很可能this问题。

private void ContextMenu_Unload(object sender, RoutedEventArgs e) 
{ 
    ContextMenu conmen = (sender as ContextMenu); 
    conmen.ClearValue(FrameworkElement.DataContextProperty); 
}