Strange WPB ListBox Behavior

Question

Я пытаюсь связать список элементов с ListBox в WPF. Элементы сгруппированы по одному значению, и каждая группа должна быть размещена в Expander. Все работает отлично, когда я не использую какие-либо пользовательские стили. Однако, когда я использую пользовательские стили (которые работают правильно с негрупповыми элементами и как независимые элементы управления), привязка не отображает никаких элементов. Ниже приведен код, который я выполняю. Любые идеи, почему элементы не отображаются в Expander?

Test.xaml:

<Window x:Class="Glossy.Test" 
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
Title="Test" Height="300" Width="300"> 
<Window.Resources> 
    <ResourceDictionary> 
     <ResourceDictionary.MergedDictionaries> 
      <ResourceDictionary Source="..\TestStyles.xaml"/> 
      <ResourceDictionary> 
       <Style x:Key="ContainerStyle" TargetType="{x:Type GroupItem}"> 
        <Setter Property="Template"> 
         <Setter.Value> 
          <ControlTemplate> 
           <Expander Header="{Binding}" IsExpanded="True"> 
            <ItemsPresenter /> 
           </Expander> 
          </ControlTemplate> 
         </Setter.Value> 
        </Setter> 
       </Style> 
      </ResourceDictionary> 
     </ResourceDictionary.MergedDictionaries> 
    </ResourceDictionary> 
</Window.Resources> 

<Grid>   
    <ListBox x:Name="TestList"> 
     <ListBox.GroupStyle> 
      <GroupStyle ContainerStyle="{StaticResource ContainerStyle}"/> 
     </ListBox.GroupStyle> 
    </ListBox> 
</Grid> 

Test.xaml.cs:

public partial class Test : Window 
{ 
    private List<Contact> _ContactItems; 
    public List<Contact> ContactItems 
    { 
     get { return _ContactItems; } 
     set { _ContactItems = value; } 
    } 

    public Test() 
    { 
     InitializeComponent(); 

     ContactItems = new List<Contact>(); 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "ABC"; 
     ContactItems.Last().Name = "Contact 1"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "ABC"; 
     ContactItems.Last().Name = "Contact 2"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "ABC"; 
     ContactItems.Last().Name = "Contact 3"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "ABC"; 
     ContactItems.Last().Name = "Contact 10"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "ABC"; 
     ContactItems.Last().Name = "Contact 11"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "ABC"; 
     ContactItems.Last().Name = "Contact 12"; 

     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "RST"; 
     ContactItems.Last().Name = "Contact 7"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "RST"; 
     ContactItems.Last().Name = "Contact 8"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "RST"; 
     ContactItems.Last().Name = "Contact 9"; 

     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "XYZ"; 
     ContactItems.Last().Name = "Contact 4"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "XYZ"; 
     ContactItems.Last().Name = "Contact 5"; 
     ContactItems.Add(new Contact()); 
     ContactItems.Last().CompanyName = "XYZ"; 
     ContactItems.Last().Name = "Contact 6"; 

     ICollectionView view = CollectionViewSource.GetDefaultView(ContactItems); 
     view.GroupDescriptions.Add(new PropertyGroupDescription("CompanyName")); 
     view.SortDescriptions.Add(new SortDescription("Name", ListSortDirection.Ascending)); 
     TestList.ItemsSource = view; 
    } 
} 

public class Contact 
{ 
    public string CompanyName { get; set; } 
    public string Name { get; set; } 

    public override string ToString() 
    { 
     return Name; 
    } 
} 

TestStyles.xaml:

<Style TargetType="{x:Type ListBox}"> 
    <Setter Property="SnapsToDevicePixels" Value="true"/> 
    <Setter Property="OverridesDefaultStyle" Value="true"/> 
    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/> 
    <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/> 
    <Setter Property="ScrollViewer.CanContentScroll" Value="true"/> 
    <Setter Property="MinWidth" Value="120"/> 
    <Setter Property="MinHeight" Value="95"/> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate TargetType="ListBox"> 
       <Grid Background="Black"> 
        <Rectangle VerticalAlignment="Stretch" 
           HorizontalAlignment="Stretch" 
           Fill="White"> 
         <Rectangle.OpacityMask> 
          <DrawingBrush> 
           <DrawingBrush.Drawing> 
            <GeometryDrawing Geometry="M65.5,33 L537.5,35 537.5,274.5 C536.5,81 119.5,177 66.5,92" Brush="#11444444"> 
             <GeometryDrawing.Pen> 
              <Pen Brush="Transparent"/> 
             </GeometryDrawing.Pen> 
            </GeometryDrawing> 
           </DrawingBrush.Drawing> 
          </DrawingBrush> 
         </Rectangle.OpacityMask> 
        </Rectangle> 
        <Border Name="Border" 
          Background="Transparent" 
          BorderBrush="Gray" 
          BorderThickness="1" 
          CornerRadius="2"> 
         <ScrollViewer Margin="0" Focusable="false"> 
          <StackPanel Margin="2" IsItemsHost="True" /> 
         </ScrollViewer> 
        </Border> 
       </Grid> 
       <ControlTemplate.Triggers> 
        <Trigger Property="IsEnabled" Value="false"> 
         <Setter TargetName="Border" Property="Background" Value="Gray" /> 
         <Setter TargetName="Border" Property="BorderBrush" Value="DimGray" /> 
        </Trigger> 
        <Trigger Property="IsGrouping" Value="true"> 
         <Setter Property="ScrollViewer.CanContentScroll" Value="false"/> 
        </Trigger> 
       </ControlTemplate.Triggers> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 
</Style> 

<Style TargetType="{x:Type ListBoxItem}"> 
    <Setter Property="SnapsToDevicePixels" Value="true"/> 
    <Setter Property="OverridesDefaultStyle" Value="true"/> 
    <Setter Property="Foreground" Value="Gray"/> 
    <Setter Property="Background" Value="Transparent"/> 
    <Setter Property="FontFamily" Value="Verdana"/> 
    <Setter Property="HorizontalAlignment" Value="Stretch"/> 
    <Setter Property="FontSize" Value="11"/> 
    <Setter Property="Margin" Value="3,1,3,1"/> 
    <Setter Property="Padding" Value="0"/> 
    <Setter Property="FontWeight" Value="Normal"/> 
    <Setter Property="VerticalAlignment" Value="Center"/> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate TargetType="ListBoxItem"> 
       <Border Name="Border" 
         Padding="2" 
         SnapsToDevicePixels="true"> 
        <ContentPresenter /> 
       </Border> 
       <ControlTemplate.Triggers> 
        <Trigger Property="IsSelected" Value="true"> 
         <Setter TargetName="Border" Property="Background" Value="Gray"/> 
        </Trigger> 
        <Trigger Property="IsEnabled" Value="false"> 
         <Setter Property="Foreground" Value="White"/> 
        </Trigger> 
       </ControlTemplate.Triggers> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 
</Style> 

<ControlTemplate x:Key="ExpanderToggleButton" TargetType="ToggleButton"> 
    <Border Name="Border" 
      CornerRadius="2,0,0,0" 
      Background="Transparent" 
      BorderBrush="LightGray" 
      BorderThickness="0,0,1,0"> 
     <Path Name="Arrow" 
       Fill="Blue" 
       HorizontalAlignment="Center" 
       VerticalAlignment="Center" 
       Data="M 0 0 L 4 4 L 8 0 Z"/> 
    </Border> 
    <ControlTemplate.Triggers> 
     <Trigger Property="ToggleButton.IsMouseOver" Value="True"> 
      <Setter TargetName="Border" Property="Background" Value="Gray" /> 
     </Trigger> 
     <Trigger Property="IsPressed" Value="True"> 
      <Setter TargetName="Border" Property="Background" Value="Black" /> 
     </Trigger> 
     <Trigger Property="IsChecked" Value="True"> 
      <Setter TargetName="Arrow" Property="Data" Value="M 0 4 L 4 0 L 8 4 Z" /> 
     </Trigger> 
     <Trigger Property="IsEnabled" Value="False"> 
      <Setter TargetName="Border" Property="Background" Value="DimGray" /> 
      <Setter TargetName="Border" Property="BorderBrush" Value="DimGray" /> 
      <Setter Property="Foreground" Value="LightGray"/> 
      <Setter TargetName="Arrow" Property="Fill" Value="LightBlue" /> 
     </Trigger> 
    </ControlTemplate.Triggers> 
</ControlTemplate> 

<Style TargetType="{x:Type Expander}"> 
    <Setter Property="Foreground" Value="White"/> 
    <Setter Property="FontFamily" Value="Verdana"/> 
    <Setter Property="FontSize" Value="11"/> 
    <Setter Property="FontWeight" Value="Normal"/> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate TargetType="Expander"> 
       <Grid> 
        <Grid.RowDefinitions> 
         <RowDefinition Height="Auto"/> 
         <RowDefinition Name="ContentRow" Height="0"/> 
        </Grid.RowDefinitions> 
        <Border Name="Border" 
          Grid.Row="0" 
          Background="Black" 
          BorderBrush="DimGray" 
          BorderThickness="1" 
          Cursor="Hand" 
          CornerRadius="2,2,0,0" > 
         <Grid HorizontalAlignment="Left"> 
          <Grid.RowDefinitions> 
           <RowDefinition Height="23"/> 
          </Grid.RowDefinitions> 
          <Grid.ColumnDefinitions> 
           <ColumnDefinition Width="20" /> 
           <ColumnDefinition Width="*" /> 
          </Grid.ColumnDefinitions> 
          <ToggleButton IsChecked="{Binding Path=IsExpanded,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}" 
              Template="{StaticResource ExpanderToggleButton}" 
              Background="Black" /> 
          <Label Grid.Column="1" 
            FontSize="14" 
            FontWeight="Normal" 
            Margin="0" 
            VerticalAlignment="Top" 
            Foreground="White" 
            FontFamily="Verdana"> 
           <ContentPresenter Grid.Column="1" 
                Margin="4,3,0,0" 
                HorizontalAlignment="Left" 
                ContentSource="Header" 
                RecognizesAccessKey="True" /> 
          </Label> 
         </Grid> 
        </Border> 
        <Border Name="Content"         
          Background="Black" 
          BorderBrush="DimGray" 
          BorderThickness="1,0,1,1" 
          Grid.Row="1" 
          CornerRadius="0,0,2,2" > 
         <Grid Background="Black"> 
          <Rectangle VerticalAlignment="Stretch" 
             HorizontalAlignment="Stretch" 
             Fill="White"> 
           <Rectangle.OpacityMask> 
            <DrawingBrush> 
             <DrawingBrush.Drawing> 
              <GeometryDrawing Geometry="M65.5,33 L537.5,35 537.5,274.5 C536.5,81 119.5,177 66.5,92" Brush="#11444444"> 
               <GeometryDrawing.Pen> 
                <Pen Brush="Transparent"/> 
               </GeometryDrawing.Pen> 
              </GeometryDrawing> 
             </DrawingBrush.Drawing> 
            </DrawingBrush> 
           </Rectangle.OpacityMask> 
          </Rectangle> 
          <ContentPresenter Margin="4" /> 
         </Grid> 
        </Border> 
       </Grid> 
       <ControlTemplate.Triggers> 
        <Trigger Property="IsExpanded" Value="True"> 
         <Setter TargetName="ContentRow" Property="Height" Value="{Binding ElementName=Content,Path=DesiredHeight}" /> 
        </Trigger> 
        <Trigger Property="IsEnabled" Value="False"> 
         <Setter TargetName="Border" Property="Background" Value="Gray" /> 
         <Setter TargetName="Border" Property="BorderBrush" Value="DimGray" /> 
         <Setter Property="Foreground" Value="White"/> 
        </Trigger> 
       </ControlTemplate.Triggers> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 
</Style> 

Answer 1

Используйте ItemsPresenter вместо StackPanel в шаблоне управления ListBox (в TestStyles.xaml).