Utilisation de CollectionViewSource dans un ItemsControl imbriqué dans un ItemsControl

Question

J'essaie d'utiliser un CollectionViewSource dans un ItemsControl qui est imbriqué dans un autre ItemsControl. Je n'ai pas d'avertissement/d'erreur XAML, mais les données ne sont pas affichées. Si je lie la propriété ItemsSource directement au ObservableCollection, il n'y a aucun problème à afficher les éléments. Mon ViewModel est essentiellement une collection imbriquée dans une autre collection.

XAML

<UserControl x:Class="View" 
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:v="clr-namespace:ViewModel" 
      xmlns:componentModel="clr-namespace:System.ComponentModel;assembly=WindowsBase" 
      mc:Ignorable="d" 
      d:DesignHeight="300" d:DesignWidth="300"> 
    <TabControl ItemsSource="{Binding Categories}" SelectedItem="{Binding SelectedCategory, Mode=TwoWay}"> 
     <TabControl.ItemContainerStyle> 
      <Style TargetType="TabItem"> 
       <Setter Property="HeaderTemplate"> 
        <Setter.Value> 
         <DataTemplate DataType="v:CategoryViewModel"> 
          <TextBlock Text="{Binding Name}"/> 
         </DataTemplate> 
        </Setter.Value> 
       </Setter> 
      </Style> 
     </TabControl.ItemContainerStyle> 
     <TabControl.ContentTemplate> 
      <DataTemplate DataType="v:CategoryViewModel"> 
       <ScrollViewer> 
        <ItemsControl ItemsSource="{Binding Groups}"> 
         <ItemsControl.ItemTemplate> 
          <DataTemplate> 
           <DataTemplate.Resources> 
            <CollectionViewSource x:Key="ValuesCollection" Source="{Binding Values}"> 
             <CollectionViewSource.SortDescriptions> 
              <componentModel:SortDescription PropertyName="Name" /> 
             </CollectionViewSource.SortDescriptions> 
            </CollectionViewSource> 
           </DataTemplate.Resources> 
           <GroupBox Header="{Binding Name}" > 
            <ItemsControl ItemsSource="{Binding Source={StaticResource ValuesCollection}}"> 
             <ItemsControl.ItemTemplate> 
              <DataTemplate> 
               <Grid Margin="10,2,10,2"> 
                <Grid.RowDefinitions> 
                 <RowDefinition/> 
                 <RowDefinition/> 
                </Grid.RowDefinitions> 
                <TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding Name}"/> 
                <TextBlock Grid.Row="1" Grid.Column="0" Text="{Binding Value}""/> 
               </Grid> 
              </DataTemplate> 
             </ItemsControl.ItemTemplate> 
            </ItemsControl> 
           </GroupBox> 
          </DataTemplate> 
         </ItemsControl.ItemTemplate> 
        </ItemsControl> 
       </ScrollViewer> 
      </DataTemplate> 
     </TabControl.ContentTemplate> 
    </TabControl> 
</UserControl> 

CategoryViewModel

namespace ViewModel 
{ 
    using System.Collections.ObjectModel; 
    using System.Diagnostics; 

    internal class CategoryViewModel : ObservableObjectBase 
    { 
     private string name; 
     private string id; 
     private int priority; 

     public CategoryViewModel() 
     { 
      this.Groups = new ObservableCollection<GroupViewModel>(); 
     } 

     public ObservableCollection<GroupViewModel> Groups { get; } 

     public string Name 
     { 
      get 
      { 
       return this.name; 
      } 

      set 
      { 
       this.SetValue(ref this.name, value); 
      } 
     } 

     public string Id 
     { 
      get 
      { 
       return this.id; 
      } 

      set 
      { 
       this.SetValue(ref this.id, value); 
      } 
     } 

     public int Priority 
     { 
      get 
      { 
       return this.priority; 
      } 

      set 
      { 
       this.SetValue(ref this.priority, value); 
      } 
     } 
    } 
} 

GroupViewModel

namespace ViewModel 
{ 
    using System.Collections.ObjectModel; 
    using System.Diagnostics; 

    internal class GroupViewModel : ObservableObjectBase 
    { 
     private string name; 
     private string id; 
     private int priority; 

     public GroupViewModel() 
     { 
      this.Values = new ObservableCollection<ValueViewModel>(); 
     } 

     public ObservableCollection<ValueViewModel> Values { get; } 

     public string Name 
     { 
      get 
      { 
       return this.name; 
      } 

      set 
      { 
       this.SetValue(ref this.name, value); 
      } 
     } 

     public string Id 
     { 
      get 
      { 
       return this.id; 
      } 

      set 
      { 
       this.SetValue(ref this.id, value); 
      } 
     } 

     public int Priority 
     { 
      get 
      { 
       return this.priority; 
      } 

      set 
      { 
       this.SetValue(ref this.priority, value); 
      } 
     } 
    } 
} 

ValueViewModel

namespace ViewModel 
{ 
    using System.Diagnostics; 

    internal class ValueViewModel : ObservableObjectBase 
    { 
     private string name; 
     private string id; 
     private string value; 
     private int priority; 

     public string Name 
     { 
      get 
      { 
       return this.name; 
      } 

      set 
      { 
       this.SetValue(ref this.name, value); 
      } 
     } 

     public string Id 
     { 
      get 
      { 
       return this.id; 
      } 

      set 
      { 
       this.SetValue(ref this.id, value); 
      } 
     } 

     public string Value 
     { 
      get 
      { 
       return this.value; 
      } 

      set 
      { 
       this.SetValue(ref this.value, value); 
      } 
     } 

     public int Priority 
     { 
      get 
      { 
       return this.priority; 
      } 

      set 
      { 
       this.SetValue(ref this.priority, value); 
      } 
     } 
    } 
} 

Une suggestion?

Merci d'avance.

Edit: Dans la sortie, je vois:

System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=Values; DataItem=null; target element is 'CollectionViewSource' (HashCode=40230093); target property is 'Source' (type 'Object')

Answer 1

Au lieu de placer la CollectionViewSource dans DataTemplate.Resources, vous devez le placer dans les ressources d'un élément cadre intérieur le DataTemplate, par exemple dans <GroupBox.Resources>

Voir les documents connexes: https://stackoverflow.com/a/6614745/5265292