如何使上下文菜单适用于 Windows 手机? [英] How to make context menu work for windows phone?

问题描述

我正在使用 Windows Phone 控制工具包中的 ContextMenu.想知道我如何知道按下了列表中的哪个列表项?似乎我可以知道选择了哪个上下文菜单，但我无法知道对哪个列表项进行了操作.请帮忙.谢谢！

I am using ContextMenu from Windows Phone Control toolkit. Wondering how do I know which list item in the list is pressed? It seems I can know which context menu is selected but I have no way to know which list item is operated on. Please help. Thanks!

        <DataTemplate x:Key="ListItemTemplate">
            <StackPanel Grid.Column="1" VerticalAlignment="Top">
                <TextBlock Tag="{Binding Index}"  Text="{Binding SName}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" />
              <toolkit:ContextMenuService.ContextMenu>
                <toolkit:ContextMenu>
                  <toolkit:MenuItem Header="Add to playlist" Click="Move_Click"/>
                </toolkit:ContextMenu>
              </toolkit:ContextMenuService.ContextMenu>
            </StackPanel>

        private void Move_Click(object sender, RoutedEventArgs e)
    {
        String name = (string)((MenuItem)sender).Header;
        // how to know which index of the item is targeted on
    }

推荐答案

我也推荐 MVVM，但它可以简化.没有必要去极端地为每个对象都拥有一个 ViewModel.关键是将命令绑定到您的 ItemsControl(例如 ListBox)的 DataContext.

I would also recommend MVVM, but it can be simplified. No need to go to the extreme of having a ViewModel for every object. The key is to bind the command to the DataContext of your ItemsControl (eg ListBox).

假设您的 ItemTemplate 用于 ListBox，ListBox 的 ItemsSource 属性绑定到您的 ViewModel.您的 xaml 将如下所示:

Let's assume that your ItemTemplate is for a ListBox, the ListBox has it's ItemsSource property bound to your ViewModel. Your xaml would look like this:

<ListBox x:Name="SongsListBox" ItemsSource="{Binding Songs}">
    <ListBox.ItemTemplate>
        <DataTemplate >
            <StackPanel >
                <TextBlock Text="{Binding SName}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" />
                <toolkit:ContextMenuService.ContextMenu>
                   <toolkit:ContextMenu>
                       <toolkit:MenuItem Header="Add to playlist" Command="{Binding DataContext.AddToPlaylistCommand, ElementName=SongsListBox}" CommandParameter="{Binding}"/>
                   </toolkit:ContextMenu>
                </toolkit:ContextMenuService.ContextMenu>
            </StackPanel>              
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

您的 ViewModel 将拥有属性 Songs，即您的模型对象的集合.它还有一个 ICommand AddToPlaylistCommand.正如我之前所说，我的最喜欢的 ICommand 实现是来自 PNP 团队的 DelegateCommand.

Your ViewModel, would then have the property Songs, that is a collection of your model object. It also has an ICommand AddToPlaylistCommand. As I've said before, my favorite implementation of ICommand is the DelegateCommand from the PNP team.

public class ViewModel : INotifyPropertyChanged
{
    public ViewModel()
    {
        Songs = new ObservableCollection<Songs>();
        AddToPlaylistCommand = new DelegateCommand<Song>(AddToPlaylist);
    }
    public ICollection<Songs> Songs { get; set; }
    public ICommand AddToPlaylistCommand  { get; private set; }

    private void AddToPlaylist(Song song)
    {
        // I have full access to my model!
        // add the item to the playlist
    }

    // Other stuff for INotifyPropertyChanged
}

这篇关于如何使上下文菜单适用于 Windows 手机?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！