Ändern des Stils eines Kombinationsfeld Dropdown

Question

Ich habe drei ComboBoxes in einem überlagerten Raster auf ein Bild. Das Raster hat eine Deckkraft von 0,5, die dann von den ComboBoxen vererbt wird, wenn sie inaktiv sind. wie Sie sehen können here.

Wenn Sie jedoch die ComboBox öffnen, wird diese Undurchsichtigkeit nicht von dem Aufklappmenü beibehalten - es hat wieder volle Opazität, wie Sie here sehen können. Gibt es eine Möglichkeit, die Drop-Downs von der ComboBox weniger undurchsichtig zu machen?

Answer 1

Sie müssen die ControlTemplate des ComboBox ändern. Sie können die Standardvorlage in Ihrem XAML-Markup mit der rechten Maustaste auf das ComboBox Element im Design-Modus in Visual Studio kopieren und die „Vorlage bearbeiten“ Option auswählen und dann die „eine Kopie bearbeiten ...“ Option,

Einmal Sie haben dies getan Sie die Opacity Eigenschaft des SystemDropShadowChrome Element im Popup einstellen könnte:

<Themes:SystemDropShadowChrome Opacity="{TemplateBinding Opacity}" ... 

Es gibt keine Möglichkeit, dies zu tun, indem Sie einfach eine Eigenschaft. Hier

ist ein Beispiel für Sie:

<ComboBox Opacity="0.5" xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero2"> 
    <ComboBox.Resources> 
     <Style x:Key="FocusVisual"> 
      <Setter Property="Control.Template"> 
       <Setter.Value> 
        <ControlTemplate> 
         <Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/> 
        </ControlTemplate> 
       </Setter.Value> 
      </Setter> 
     </Style> 
     <LinearGradientBrush x:Key="ComboBox.Static.Background" EndPoint="0,1" StartPoint="0,0"> 
      <GradientStop Color="#FFF0F0F0" Offset="0.0"/> 
      <GradientStop Color="#FFE5E5E5" Offset="1.0"/> 
     </LinearGradientBrush> 
     <SolidColorBrush x:Key="ComboBox.Static.Border" Color="#FFACACAC"/> 
     <SolidColorBrush x:Key="ComboBox.Static.Editable.Background" Color="#FFFFFFFF"/> 
     <SolidColorBrush x:Key="ComboBox.Static.Editable.Border" Color="#FFABADB3"/> 
     <SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Background" Color="Transparent"/> 
     <SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Border" Color="Transparent"/> 
     <SolidColorBrush x:Key="ComboBox.MouseOver.Glyph" Color="#FF000000"/> 
     <LinearGradientBrush x:Key="ComboBox.MouseOver.Background" EndPoint="0,1" StartPoint="0,0"> 
      <GradientStop Color="#FFECF4FC" Offset="0.0"/> 
      <GradientStop Color="#FFDCECFC" Offset="1.0"/> 
     </LinearGradientBrush> 
     <SolidColorBrush x:Key="ComboBox.MouseOver.Border" Color="#FF7EB4EA"/> 
     <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Background" Color="#FFFFFFFF"/> 
     <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Border" Color="#FF7EB4EA"/> 
     <LinearGradientBrush x:Key="ComboBox.MouseOver.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0"> 
      <GradientStop Color="#FFEBF4FC" Offset="0.0"/> 
      <GradientStop Color="#FFDCECFC" Offset="1.0"/> 
     </LinearGradientBrush> 
     <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Button.Border" Color="#FF7EB4EA"/> 
     <SolidColorBrush x:Key="ComboBox.Pressed.Glyph" Color="#FF000000"/> 
     <LinearGradientBrush x:Key="ComboBox.Pressed.Background" EndPoint="0,1" StartPoint="0,0"> 
      <GradientStop Color="#FFDAECFC" Offset="0.0"/> 
      <GradientStop Color="#FFC4E0FC" Offset="1.0"/> 
     </LinearGradientBrush> 
     <SolidColorBrush x:Key="ComboBox.Pressed.Border" Color="#FF569DE5"/> 
     <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Background" Color="#FFFFFFFF"/> 
     <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Border" Color="#FF569DE5"/> 
     <LinearGradientBrush x:Key="ComboBox.Pressed.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0"> 
      <GradientStop Color="#FFDAEBFC" Offset="0.0"/> 
      <GradientStop Color="#FFC4E0FC" Offset="1.0"/> 
     </LinearGradientBrush> 
     <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Button.Border" Color="#FF569DE5"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Glyph" Color="#FFBFBFBF"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Background" Color="#FFF0F0F0"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Border" Color="#FFD9D9D9"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Background" Color="#FFFFFFFF"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Border" Color="#FFBFBFBF"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Background" Color="Transparent"/> 
     <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Border" Color="Transparent"/> 
     <SolidColorBrush x:Key="ComboBox.Static.Glyph" Color="#FF606060"/> 
     <Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}"> 
      <Setter Property="OverridesDefaultStyle" Value="true"/> 
      <Setter Property="IsTabStop" Value="false"/> 
      <Setter Property="Focusable" Value="false"/> 
      <Setter Property="ClickMode" Value="Press"/> 
      <Setter Property="Template"> 
       <Setter.Value> 
        <ControlTemplate TargetType="{x:Type ToggleButton}"> 
         <Border x:Name="templateRoot" BorderBrush="{StaticResource ComboBox.Static.Border}" BorderThickness="{TemplateBinding BorderThickness}" Background="{StaticResource ComboBox.Static.Background}" SnapsToDevicePixels="true"> 
          <Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="true" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"> 
           <Path x:Name="arrow" Data="F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z" Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/> 
          </Border> 
         </Border> 
         <ControlTemplate.Triggers> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/> 
            <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/> 
            <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/> 
            <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Border}"/> 
           <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Background}"/> 
           <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Border}"/> 
          </MultiDataTrigger> 
          <Trigger Property="IsMouseOver" Value="true"> 
           <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.MouseOver.Glyph}"/> 
          </Trigger> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Border}"/> 
          </MultiDataTrigger> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Border}"/> 
           <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Background}"/> 
           <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Border}"/> 
          </MultiDataTrigger> 
          <Trigger Property="IsPressed" Value="true"> 
           <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Pressed.Glyph}"/> 
          </Trigger> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Border}"/> 
          </MultiDataTrigger> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Border}"/> 
           <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Background}"/> 
           <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Border}"/> 
          </MultiDataTrigger> 
          <Trigger Property="IsEnabled" Value="false"> 
           <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Disabled.Glyph}"/> 
          </Trigger> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Border}"/> 
          </MultiDataTrigger> 
          <MultiDataTrigger> 
           <MultiDataTrigger.Conditions> 
            <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/> 
            <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/> 
           </MultiDataTrigger.Conditions> 
           <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Background}"/> 
           <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Border}"/> 
           <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Background}"/> 
           <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Border}"/> 
          </MultiDataTrigger> 
         </ControlTemplate.Triggers> 
        </ControlTemplate> 
       </Setter.Value> 
      </Setter> 
     </Style> 
     <SolidColorBrush x:Key="TextBox.Static.Background" Color="#FFFFFFFF"/> 
     <Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}"> 
      <Setter Property="OverridesDefaultStyle" Value="true"/> 
      <Setter Property="AllowDrop" Value="true"/> 
      <Setter Property="MinWidth" Value="0"/> 
      <Setter Property="MinHeight" Value="0"/> 
      <Setter Property="FocusVisualStyle" Value="{x:Null}"/> 
      <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/> 
      <Setter Property="Stylus.IsFlicksEnabled" Value="False"/> 
      <Setter Property="Template"> 
       <Setter.Value> 
        <ControlTemplate TargetType="{x:Type TextBox}"> 
         <ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/> 
        </ControlTemplate> 
       </Setter.Value> 
      </Setter> 
     </Style> 
     <ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}"> 
      <Grid x:Name="templateRoot" SnapsToDevicePixels="true"> 
       <Grid.ColumnDefinitions> 
        <ColumnDefinition Width="*"/> 
        <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/> 
       </Grid.ColumnDefinitions> 
       <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom"> 
        <Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}"> 
         <Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"> 
          <ScrollViewer x:Name="DropDownScrollViewer"> 
           <Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled"> 
            <Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0"> 
             <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/> 
            </Canvas> 
            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/> 
           </Grid> 
          </ScrollViewer> 
         </Border> 
        </Themes:SystemDropShadowChrome> 
       </Popup> 
       <ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/> 
       <Border x:Name="border" Background="{StaticResource TextBox.Static.Background}" Margin="{TemplateBinding BorderThickness}"> 
        <TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/> 
       </Border> 
      </Grid> 
      <ControlTemplate.Triggers> 
       <Trigger Property="IsEnabled" Value="false"> 
        <Setter Property="Opacity" TargetName="border" Value="0.56"/> 
       </Trigger> 
       <Trigger Property="IsKeyboardFocusWithin" Value="true"> 
        <Setter Property="Foreground" Value="Black"/> 
       </Trigger> 
       <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true"> 
        <Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/> 
        <Setter Property="Color" TargetName="shadow" Value="#71000000"/> 
       </Trigger> 
       <Trigger Property="HasItems" Value="false"> 
        <Setter Property="Height" TargetName="dropDownBorder" Value="95"/> 
       </Trigger> 
       <MultiTrigger> 
        <MultiTrigger.Conditions> 
         <Condition Property="IsGrouping" Value="true"/> 
         <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/> 
        </MultiTrigger.Conditions> 
        <Setter Property="ScrollViewer.CanContentScroll" Value="false"/> 
       </MultiTrigger> 
       <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false"> 
        <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/> 
        <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/> 
       </Trigger> 
      </ControlTemplate.Triggers> 
     </ControlTemplate> 
     <Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}"> 
      <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/> 
      <Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/> 
      <Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Border}"/> 
      <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/> 
      <Setter Property="BorderThickness" Value="1"/> 
      <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/> 
      <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/> 
      <Setter Property="Padding" Value="6,3,5,3"/> 
      <Setter Property="ScrollViewer.CanContentScroll" Value="true"/> 
      <Setter Property="ScrollViewer.PanningMode" Value="Both"/> 
      <Setter Property="Stylus.IsFlicksEnabled" Value="False"/> 
      <Setter Property="Template" Value="{StaticResource ComboBoxTemplate}"/> 
      <Style.Triggers> 
       <Trigger Property="IsEditable" Value="true"> 
        <Setter Property="IsTabStop" Value="false"/> 
        <Setter Property="Padding" Value="2"/> 
        <Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/> 
       </Trigger> 
      </Style.Triggers> 
     </Style> 
    </ComboBox.Resources> 
    <ComboBox.Template> 
     <ControlTemplate TargetType="{x:Type ComboBox}"> 
      <Grid x:Name="templateRoot" SnapsToDevicePixels="true"> 
       <Grid.ColumnDefinitions> 
        <ColumnDefinition Width="*"/> 
        <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/> 
       </Grid.ColumnDefinitions> 
       <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom"> 
        <Themes:SystemDropShadowChrome Opacity="{TemplateBinding Opacity}" x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}"> 
         <Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"> 
          <ScrollViewer x:Name="DropDownScrollViewer"> 
           <Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled"> 
            <Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0"> 
             <Rectangle x:Name="opaqueRect" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/> 
            </Canvas> 
            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/> 
           </Grid> 
          </ScrollViewer> 
         </Border> 
        </Themes:SystemDropShadowChrome> 
       </Popup> 
       <ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/> 
       <ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/> 
      </Grid> 
      <ControlTemplate.Triggers> 
       <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true"> 
        <Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/> 
        <Setter Property="Color" TargetName="shadow" Value="#71000000"/> 
       </Trigger> 
       <Trigger Property="HasItems" Value="false"> 
        <Setter Property="Height" TargetName="dropDownBorder" Value="95"/> 
       </Trigger> 
       <MultiTrigger> 
        <MultiTrigger.Conditions> 
         <Condition Property="IsGrouping" Value="true"/> 
         <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/> 
        </MultiTrigger.Conditions> 
        <Setter Property="ScrollViewer.CanContentScroll" Value="false"/> 
       </MultiTrigger> 
       <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false"> 
        <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/> 
        <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/> 
       </Trigger> 
      </ControlTemplate.Triggers> 
     </ControlTemplate> 
    </ComboBox.Template> 
    <ComboBoxItem>1</ComboBoxItem> 
    <ComboBoxItem>2</ComboBoxItem> 
    <ComboBoxItem>3</ComboBoxItem> 
</ComboBox> 

Vergessen Sie nicht, einen Verweis auf PresentationFramework.Aero2 hinzuzufügen. Hier befindet sich die Klasse SystemDropShadowChrome, die Teil der Standardvorlage für Windows 8+ ist.