如何更改LongListSelector SelectionChanged方法中的圖像？

Question

我的Windows Phone應用程序中有一個LongListSelector。 LLS爲每個項目都有一個Image和TextBlock。如何在用戶更改選擇時更改圖像？我應該在我的SelectionChanged方法中寫什麼？

<phone:LongListSelector x:Name="MainLongListSelector" ItemsSource="{Binding Items}" SelectionChanged="MainLongListSelector_SelectionChanged"> 
    <phone:LongListSelector.ItemTemplate> 
      <DataTemplate> 
       <StackPanel Orientation="Horizontal"> 
        <Image Name="PlayPause" Source="/Assets/transport.play.png"/> 
        <StackPanel> 
         <TextBlock Text="{Binding LineOne}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/> 
        </StackPanel> 
       </StackPanel> 
      </DataTemplate> 
    </phone:LongListSelector.ItemTemplate> 
</phone:LongListSelector> 

Answer 1

<phone:LongListSelector x:Name="MainLongListSelector" DataContext="{Binding listData}" IsGroupingEnabled="False" SelectionChanged="MainLongListSelector_SelectionChanged_1"> 
      <phone:LongListSelector.ItemTemplate> 
       <DataTemplate> 
        <StackPanel Orientation="Horizontal"> 
         <Image Name="PlayPause" Source="{Binding ImgUrl}" Height="100" Stretch="Fill"/> 
         <StackPanel> 
          <TextBlock Text="{Binding ImgText}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/> 
         </StackPanel> 
        </StackPanel> 
       </DataTemplate> 
      </phone:LongListSelector.ItemTemplate> 
     </phone:LongListSelector> 

的XAML背後：

ObservableCollection<LongListData> listData = new ObservableCollection<LongListData>(); 

    listData.Add(new LongListData() { ImgText = "Image1", ImgUrl = new Uri("Images/1.jpg", UriKind.Relative) }); 
    listData.Add(new LongListData() { ImgText = "Image2", ImgUrl = new Uri("Images/2.jpg", UriKind.Relative) }); 
    listData.Add(new LongListData() { ImgText = "Image3", ImgUrl = new Uri("Images/3.jpg", UriKind.Relative) }); 
    listData.Add(new LongListData() { ImgText = "Image4", ImgUrl = new Uri("Images/4.jpg", UriKind.Relative) }); 

    MainLongListSelector.ItemsSource = listData; 

在selectionChanged方法

private void MainLongListSelector_SelectionChanged(object sender, SelectionChangedEventArgs e) 
    { 
     var res = (sender as LongListSelector).SelectedItem as LongListData; 
     int index = listData.IndexOf(res); 
     //mark 1 
     var newData = new LongListData() { ImgText = res.ImgText, ImgUrl = new Uri("Images/2.jpg", UriKind.Relative) }; 
     listData.RemoveAt(index); 
     listData.Insert(index, newData); 
    } 

在C＃代碼定義class

public class LongListData 
    { 
     public Uri ImgUrl { get; set; } 
     public string ImgText { get; set; } 
    } 

您可以在代碼中'mark1'隨機或根據您的需要使用圖像。