Question

当我试图学习数据绑定时，我发现其中一个快速启动示例无效。你能告诉我它是错还是我错了？

http://create.msdn.com/en-US/education/quickstarts/Data_Binding_to_Controls#DisplayingItemsWithDataTemplate

该示例使用CollectionView Source和ObservableCollection类将数据动态绑定到UI元素。我使用了listpicker而不是组合框。然而，当列表选择器中的选择发生变化时，我发现文本块没有改变。我是否必须实施更改的INotifyProperty？以下是我的C＃代码

namespace binding3
{
public partial class MainPage : PhoneApplicationPage
{
public ObservableCollection<Recording> MyMusic = new ObservableCollection<Recording>();
// Constructor
public MainPage()
{
    InitializeComponent();
    MyMusic.Add(new Recording("Chris Sells", "Chris Sells Live", new DateTime(2008, 2, 5)));
    MyMusic.Add(new Recording("Luka Abrus", "The Road to Redmond", new DateTime(2007, 4, 3)));
    MyMusic.Add(new Recording("Jim Hance", "Best of Jim Hance", new DateTime(2007, 3, 6)));
    //listPicker1.DataContext = MyMusic;
    //RecordingDetails.DataContext = new CollectionViewSource { Source = MyMusic };
    LayoutRoot.DataContext = new CollectionViewSource { Source = MyMusic };
}

public class Recording 
{
    public Recording() { }
    public Recording(string artistName, string cdName, DateTime release)
    {
        Artist = artistName;
        Name = cdName;
        ReleaseDate = release;
    }

    public string Artist { get; set; }
    public string Name { get; set; }
    public DateTime ReleaseDate { get; set; }

    public override string ToString()
    {
        return Name + " by " + Artist + ", Released: " + ReleaseDate.ToShortDateString();
    }

}

这就是xaml设计

<!--ContentPanel - place additional content here-->
<StackPanel x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
    <toolkit:ListPicker Height="150" HorizontalAlignment="Left" Margin="5" x:Name="listPicker1"
                        VerticalAlignment="Top" Width="400" ItemsSource="{Binding}" FontSize="18">
        <toolkit:ListPicker.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Horizontal" Margin="2">
                    <TextBlock Text="Artist:" Margin="2"/>
                    <TextBlock Text="{Binding Artist}" Margin="2"/>
                    <TextBlock Text="CD:" Margin="10,2,0,2"/>
                    <TextBlock Text="{Binding Name}" Margin="2"/>
                </StackPanel>
            </DataTemplate>
        </toolkit:ListPicker.ItemTemplate>
    </toolkit:ListPicker>
    <StackPanel x:Name="RecordingDetails">
        <TextBlock Text="{Binding Artist}" Margin="5,0,0,0"/>
        <TextBlock Text="{Binding Name}" Margin="5,0,0,0"/>
        <TextBlock Text="{Binding ReleaseDate}" Margin="5,0,0,0"/>
    </StackPanel>
</StackPanel>

谢谢，

Alfah

Answer 1

当您像这样修改xaml时，代码可以正常工作

<StackPanel x:Name="RecordingDetails">
            <TextBlock Text="{Binding SelectedItem.Artist, ElementName= listPicker1}" Margin="5,0,0,0"/>
            <TextBlock Text="{Binding SelectedItem.Name, ElementName= listPicker1}" Margin="5,0,0,0"/>
            <TextBlock Text="{Binding SelectedItem.ReleaseDate,ElementName= listPicker1}" Margin="5,0,0,0"/>
 </StackPanel>

您需要将listpicker的所选项目绑定到文本块，以便在更改选择时更新文本块。不知道是否有更好的方法来做到这一点。无论如何，这解决了这个问题。

Alfah

数据绑定的问题WP7中的快速入门示例

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