Xaml WP8 toolkit上下文菜单项未选中，处于保留状态

我的ContextMenu有点问题，有时单击ContextMenu时长列表中的项目没有被选中，这给了我一个问题，我不知道用户单击了什么项目。如果我先单击该项，然后按住关联菜单，它是否工作，但我如何使每次用户单击并按住时都工作

这是我的xaml

<phone:LongListSelector x:Name="List"
                        Margin="0,0,-12,0" 
                        ItemsSource="{Binding ListItems}"
                        Height="470" Tap="List_OnTap">
    <phone:LongListSelector.ItemTemplate>
        <DataTemplate>
            <StackPanel Margin="0,0,0,17">
                <TextBlock Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                    <toolkit:ContextMenuService.ContextMenu>
                        <toolkit:ContextMenu IsZoomEnabled="false">
                            <toolkit:MenuItem Header="Add as favorit" 
                                              Click="AddFavorite" />
                        </toolkit:ContextMenu>
                    </toolkit:ContextMenuService.ContextMenu>
                </TextBlock>
            </StackPanel>
        </DataTemplate>
    </phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>

---

您可以从上下文菜单本身获取该项。菜单将其DataContext设置为要绑定到的元素。只需获取DataContext，您就可以离开了

private void AddFavorite(object sender, RoutedEventArgs e)
{
    var element = (FrameworkElement)sender;
    ItemViewModel obj = element.DataContext as ItemViewModel;
    if (obj == null) return;

    NavigationService.Navigate(new Uri("/Page.xaml?id=" + obj.Id + "&fav=true", UriKind.Relative));
}

private void AddFavorite(object sender, RoutedEventArgs e)
{
    var element = (FrameworkElement)sender;
    ItemViewModel obj = element.DataContext as ItemViewModel;
    if (obj == null) return;

    NavigationService.Navigate(new Uri("/Page.xaml?id=" + obj.Id + "&fav=true", UriKind.Relative));
}