xaml - WP8 工具包 contextMenu 项目未选择暂停

Question

我的 ContextMenu 有一点问题，有时单击 ContextMenu 时未在 LongList 中选择该项目，这给了我一个问题，即我不知道用户单击了哪个项目。如果我先单击该项目，然后按住上下文菜单，它会起作用，但是每次用户单击并按住时，我怎样才能使它起作用？

这是我的xml

<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>

我的代码在后面

private void AddFavorite(object sender, RoutedEventArgs e)
{
    ItemViewModel obj = List.SelectedItem as ItemViewModel;
    if (obj == null) return;
    NavigationService.Navigate(new Uri("/Page.xaml?id=" + obj.Id + "&fav=true", UriKind.Relative));
}

Answer 1

您可以从 ContextMenu 本身获取项目。菜单将其 DataContext 设置为要绑定的元素。只需获取 DataContext 就可以了！

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));
}