創建基於TreeView控件在Silverlight

Question

我有一個樹節點類以下屬性

public string Name { get; set; } 
public string Description { get; set; } 
public bool AllowMultiples { get; set; } 
private ObservableCollection<TreeNode> _childNodes = new ObservableCollection<TreeNode>(); 

在我的UI我想在左側面板和右側選擇項目的詳細信息顯示樹主/詳細信息視圖。

我的XAML看起來像以下：

<UserControl.Resources> 
    <win:HierarchicalDataTemplate x:Key="ChildTemplate" ItemsSource="{Binding ChildNodes}"> 
     <TextBlock FontStyle="Italic" Text="{Binding Path=Name}" /> 
    </win:HierarchicalDataTemplate>   
    <win:HierarchicalDataTemplate x:Key="NameTemplate" 
    ItemsSource="{Binding Path=ChildNodes}" 
    ItemTemplate="{StaticResource ChildTemplate}"> 
     <TextBlock Text="{Binding Path=Name}" FontWeight="Bold" /> 
    </win:HierarchicalDataTemplate>   
</UserControl.Resources> 
    <Grid x:Name="LayoutRoot" Background="White"> 
    <Grid.RowDefinitions> 
     <RowDefinition Height="20"></RowDefinition> 
     <RowDefinition Height="*"></RowDefinition> 
    </Grid.RowDefinitions> 
    <Grid.ColumnDefinitions> 
     <ColumnDefinition Width="Auto"></ColumnDefinition> 
     <ColumnDefinition Width="*"></ColumnDefinition> 
    </Grid.ColumnDefinitions> 
    <TextBlock Text="Document Hierarchy" Margin="0,0,43,0" FontSize="13" /> 
    <toolkit:TreeViewDragDropTarget Grid.Row="1" Grid.Column="0" BorderThickness="-1"> 
     <controls:TreeView BorderThickness="0" ItemTemplate="{StaticResource ChildTemplate}" x:Name="treeView" ItemsSource="{Binding}">     
     </controls:TreeView> 
    </toolkit:TreeViewDragDropTarget> 
    <TextBlock Text="Properties" FontSize="11" Grid.Column="1" Grid.Row="0" /> 
    <Grid Grid.Row="1" Grid.Column="1"> 
     <Grid.RowDefinitions> 
      <RowDefinition Height="Auto" ></RowDefinition> 
      <RowDefinition Height="*"></RowDefinition>     
     </Grid.RowDefinitions> 
     <Grid.ColumnDefinitions> 
      <ColumnDefinition Width="*"></ColumnDefinition> 
      <ColumnDefinition Width="*"></ColumnDefinition> 
      <ColumnDefinition Width="*"></ColumnDefinition> 
     </Grid.ColumnDefinitions> 
     <TextBlock x:Name="AlloMultPropLabel" Text="Allow Multiple" Grid.Column="0" Grid.Row="0"></TextBlock> 
     <RadioButton x:Name="AllowMulti" GroupName="GrpAllowMulti" Content="True" Grid.Column="1" Grid.Row="0"/> 
     <RadioButton x:Name="AllowMulti2" GroupName="GrpAllowMulti" Content="False" Grid.Column="2" Grid.Row="0" IsChecked="True" /> 
     <TextBlock x:Name="DescPropLabel" Text="Description" HorizontalAlignment="Left" Width="74" Grid.Row="2" ></TextBlock> 
     <TextBox x:Name="DescProp" Grid.Column="1" Grid.Row="2" Grid.ColumnSpan="2" Text="{Binding Description}" />   
    </Grid> 

使用http://www.silverlight.net/learn/quickstarts/bindingtocontrols/作爲我參考，我設置了LayoutRoot.DataContext到如下CollectionViewSource：

public ObservableCollection<TreeNode> itemsSource = new ObservableCollection<TreeNode>() 
    { 
     new TreeNode("Root", "ths is test"), 
     new TreeNode("Secondary","Second node"), 
}; 


    public MainPage() 
    { 
     InitializeComponent(); 
     //treeView.DataContext = itemsSource; 
     LayoutRoot.DataContext = new CollectionViewSource { Source = itemsSource }; 

    } 

當我運行這個項目，我注意到，說明始終設置爲第一項描述。它不會根據選擇而改變。

任何指針得到這個權利？

Answer 1

您已將文本框綁定到「{綁定說明}」。它將使用與TreeView開始的相同的DataContext，因此它顯示頂部項目的描述。

爲了讓文本框跟隨樹中選定的項目，它的數據上下文需要綁定到Treeview的SelectedItem。我會傾向於把「詳細信息」顯示在自己的網格，並在那裏經營的佈局，這將是更新DataContext的好去處： -

<Grid DataContext="{Binding SelectedItem, ElementName=treeView}"> 
    <Grid.ColumnDefinitions> 
     <Grid.ColumnDefinition Width="Auto" /> 
     <Grid.ColumnDefinition Width="*" /> 
    </Grid.ColumnDefinitions> 
    <Grid.RowDefinitions> 
     <Grid.RowDefinition Height="Auto" /> 
     <Grid.RowDefinition Height="Auto" /> 
    </Grid.RowDefinitions> 

    <TextBlock Text="Name" Grid.Row="0" Grid.Column="0" /> 
    <TextBox Text="{Binding Name}" Grid.Row="0" Grid.Column="1"/> 

    <TextBlock Text="Description" Grid.Row="1" Grid.Column="0" /> 
    <TextBox Text="{Binding Description}" Grid.Row="1" Grid.Column="1"/> 
</Grid> 

注意在網格的DataContext它綁定使用treeView作爲源對象並綁定到SelectedItem。