Silverlight的数据绑定错误 [英] Silverlight DataBinding Error

问题描述

我有一个的GridView 具有 RowDetail 。我想每次用户点击行得到一些细节上的数据库，我用的Telerik 的GridView 。在正常的方式，它是不可能的，或者至少我不知道怎么回事，因为 RowDetail 上下文直接绑定到网格的DataContext ，我要的是比什么GridRow包含它。我发现是，也许我可以设置RowDetailTemplate的DataContext为用户控件通过命名用户控件这样我可以参考RowDetail到其他模式。 我的code是这样的

I've a GridView which has RowDetail. I want to each time user clicks on the rows get some detail from database, I use Telerik GridView. In normal way it's not possible or at least I don't know how, because RowDetail context binded directly to the grid DataContext, what I want is more than what GridRow contains it. What I found is maybe I can set RowDetailTemplate DataContext to UserControl by naming the UserControl so I can reference RowDetail to other model. My code is something like this

    <UserControl
    x:Name="mainPageView"
    x:Class="Project.Client.TestView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView" 
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <UserControl.Resources>
        <DataTemplate x:Key="ContactRowDetailTemplate" >
            <Grid Background="Transparent"
                DataContext="{Binding DataContext.ContactStatModel, 
                ElementName=mainPageView,Mode=OneTime}">
                <Grid.RowDefinitions>
                    <RowDefinition Height="28" />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                </Grid.ColumnDefinitions>
                <TextBlock Text="Sent SMS Count" Grid.Column="0" Grid.Row="0" />
                <TextBlock Text=":" Grid.Column="1" Grid.Row="0" />
                <TextBlock Text="{Binding SMSCount}" Grid.Column="2" Grid.Row="0" />

            </Grid>
        </DataTemplate>
    </UserControl.Resources>

    <telerik:RadGridView  
        x:Name="gridView"
        AutoGenerateColumns="False" Height="Auto" Grid.Row="3"
        ItemsSource="{Binding VOutboxList, Mode=TwoWay}"
        SelectedItem="{Binding VOutboxModel, Mode=TwoWay}"
        RowDetailsTemplate="{StaticResource ContactRowDetailTemplate}"
        LoadingRowDetails="gridView_LoadingRowDetails">
        <telerik:RadGridView.Columns>
            <telerik:GridViewDataColumn UniqueName="FirstName"  Header="First Name" Width="150" />
            <telerik:GridViewDataColumn UniqueName="LastName" Header="Last Name" Width="150" />
        </telerik:RadGridView.Columns>
    </telerik:RadGridView>

</UserControl>

但是，这一次我得到这个异​​常

But this time I get this exception

{Error: System.Exception: BindingExpression_CannotFindElementName}

任何意见将是有益的。 顺祝商祺。

Any advice will be helpful. Best Regards.

推荐答案

这样做的原因是，WPF的和Silverlights DataGrid列生活逻辑树之外，从而使其无法使用绑定源中指定使用的ElementName这是常见的，当引用视图模型属性，如从DataGrid的模板列中的命令。有关此问题的详细信息请参阅：<一href="http://blogs.msdn.com/b/jaimer/archive/2008/11/22/forwarding-the-datagrid-s-datacontext-to-its-columns.aspx" rel="nofollow">http://blogs.msdn.com/b/jaimer/archive/2008/11/22/forwarding-the-datagrid-s-datacontext-to-its-columns.aspx

The reason for this is that WPF's and Silverlights DataGrid columns live outside the logical tree and thus make it impossible to use a binding source specified using ElementName which is common when referencing ViewModel properties such as commands from within DataGrid Template Columns. For more information about this problem see: http://blogs.msdn.com/b/jaimer/archive/2008/11/22/forwarding-the-datagrid-s-datacontext-to-its-columns.aspx

以下行为的柱和它周围的世界之间的胶水类。它是为Silverlight的内置数据网格编写的，但应该很容易适应它的网格的Telerik。它可以是这样的：

The class below act's as glue between the column and the world around it. It was written for Silverlight's built-in DataGrid but should be easy enough to adapt it for the Telerik Grid. It can be used like this:

<DataTemplate x:Key="ContactRowDetailTemplate" >
  <Grid Background="Transparent"
    DataContext="{Binding ParentDataGrid.DataContext.ContactStatModel, 
    ElementName=shim,Mode=OneTime}">
        <Shims:DataGridShim x:Name="shim"/>
    <Grid.RowDefinitions>
      <RowDefinition Height="28" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
      <ColumnDefinition Width="Auto" />
      <ColumnDefinition Width="Auto" />
      <ColumnDefinition Width="Auto" />
    </Grid.ColumnDefinitions>
    <TextBlock Text="Sent SMS Count" Grid.Column="0" Grid.Row="0" />
    <TextBlock Text=":" Grid.Column="1" Grid.Row="0" />
    <TextBlock Text="{Binding SMSCount}" Grid.Column="2" Grid.Row="0" />
  </Grid>
</DataTemplate>

public class DataGridShim : FrameworkElement
{
  /// <summary>
  /// Initializes a new instance of the <see cref="DataGridShim"/> class.
  /// prepares the ParentDataGrid property for consumption by sibling elements in the DataTemplate
  /// </summary>
  public DataGridShim()
  {
    Loaded += (s, re) =>
    {
      ParentDataGrid = GetContainingDataGrid(this);
    };
  }

  /// <summary>
  /// Gets or sets the parent data grid.
  /// </summary>
  /// <value>
  /// The parent data grid.
  /// </value>
  public DataGrid ParentDataGrid { get; protected set; }

  /// <summary>
  /// Walks the Visual Tree until the DataGrid parent is found and returns it
  /// </summary>
  /// <param name="value">The value.</param>
  /// <returns>The containing datagrid</returns>
  private static DataGrid GetContainingDataGrid(DependencyObject value)
  {
    if (value != null)
    {
      DependencyObject parent = VisualTreeHelper.GetParent(value);
      if (parent != null)
      {
        var grid = parent as DataGrid;
        if (grid != null)
          return grid;

        return GetContainingDataGrid(parent);
      }

      return null;
    }

    return null;
  }
}

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