TreeView Styles and Templates

This topic describes the styles and templates for the TreeView control. You can modify the default ControlTemplate to give the control a unique appearance. For more information, see Customizing the Appearance of an Existing Control by Creating a ControlTemplate.

TreeView Parts

The TreeView control does not have any named parts.

When you create a ControlTemplate for an TreeView, your template might contain a ItemsPresenter within a ScrollViewer. (The ItemsPresenter displays each item in the TreeView; the ScrollViewer enables scrolling within the control). If the ItemsPresenter is not the direct child of the ScrollViewer, you must give the ItemsPresenter the name, ItemsPresenter.

TreeView States

The following table lists the visual states for the TreeView control.

VisualState Name VisualStateGroup Name Description
Valid ValidationStates The control uses the Validation class and the HasError attached property is false.
InvalidFocused ValidationStates The HasError attached property is true has the control has focus.
InvalidUnfocused ValidationStates The HasError attached property is true has the control does not have focus.

TreeViewItem Parts

The following table lists the named parts for the TreeViewItem control.

Part Type Description
PART_Header FrameworkElement A visual element that contains that header content of the TreeView control.

TreeViewItem States

The following table lists the visual states for TreeViewItem control.

VisualState Name VisualStateGroup Name Description
Normal CommonStates The default state.
MouseOver CommonStates The mouse pointer is positioned over the TreeViewItem.
Disabled CommonStates The TreeViewItem is disabled.
Focused FocusStates The TreeViewItem has focus.
Unfocused FocusStates The TreeViewItem does not have focus.
Expanded ExpansionStates The TreeViewItem control is expanded.
Collapsed ExpansionStates The TreeViewItem control is collapsed.
HasItems HasItemsStates The TreeViewItem has items.
NoItems HasItemsStates The TreeViewItem does not have items.
Selected SelectionStates The TreeViewItem is selected.
SelectedInactive SelectionStates The TreeViewItem is selected but not active.
Unselected SelectionStates The TreeViewItem is not selected.
Valid ValidationStates The control uses the Validation class and the HasError attached property is false.
InvalidFocused ValidationStates The HasError attached property is true has the control has focus.
InvalidUnfocused ValidationStates The HasError attached property is true has the control does not have focus.

TreeView ControlTemplate Example

The following example shows how to define a ControlTemplate for the TreeView control and its associated types.

<Style x:Key="{x:Type TreeView}"
       TargetType="TreeView">
  <Setter Property="OverridesDefaultStyle"
          Value="True" />
  <Setter Property="SnapsToDevicePixels"
          Value="True" />
  <Setter Property="ScrollViewer.HorizontalScrollBarVisibility"
          Value="Auto" />
  <Setter Property="ScrollViewer.VerticalScrollBarVisibility"
          Value="Auto" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="TreeView">
        <Border Name="Border"
                CornerRadius="1"
                BorderThickness="1">
          <Border.BorderBrush>
            <SolidColorBrush Color="{DynamicResource BorderMediumColor}" />
          </Border.BorderBrush>
          <Border.Background>
            <SolidColorBrush Color="{DynamicResource ControlLightColor}" />
          </Border.Background>
          <ScrollViewer Focusable="False"
                        CanContentScroll="False"
                        Padding="4">
            <ItemsPresenter />
          </ScrollViewer>
        </Border>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

<Style x:Key="ExpandCollapseToggleStyle"
       TargetType="ToggleButton">
  <Setter Property="Focusable"
          Value="False" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="ToggleButton">
        <Grid Width="15"
              Height="13"
              Background="Transparent">
          <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="CheckStates">
              <VisualState x:Name="Checked">
                <Storyboard>
                  <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
                                                 Storyboard.TargetName="Collapsed">
                    <DiscreteObjectKeyFrame KeyTime="0"
                                            Value="{x:Static Visibility.Hidden}" />
                  </ObjectAnimationUsingKeyFrames>
                  <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
                                                 Storyboard.TargetName="Expanded">
                    <DiscreteObjectKeyFrame KeyTime="0"
                                            Value="{x:Static Visibility.Visible}" />
                  </ObjectAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
              <VisualState x:Name="Unchecked" />
              <VisualState x:Name="Indeterminate" />
            </VisualStateGroup>
          </VisualStateManager.VisualStateGroups>
          <Path x:Name="Collapsed"
                HorizontalAlignment="Left"
                VerticalAlignment="Center"
                Margin="1,1,1,1"
                Data="M 4 0 L 8 4 L 4 8 Z">
            <Path.Fill>
              <SolidColorBrush Color="{DynamicResource GlyphColor}" />
            </Path.Fill>
          </Path>
          <Path x:Name="Expanded"
                HorizontalAlignment="Left"
                VerticalAlignment="Center"
                Margin="1,1,1,1"
                Data="M 0 4 L 8 4 L 4 8 Z"
                Visibility="Hidden">
            <Path.Fill>
              <SolidColorBrush Color="{DynamicResource GlyphColor}" />
            </Path.Fill>
          </Path>
        </Grid>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>
<Style x:Key="TreeViewItemFocusVisual">
  <Setter Property="Control.Template">
    <Setter.Value>
      <ControlTemplate>
        <Border>
          <Rectangle Margin="0,0,0,0"
                     StrokeThickness="5"
                     Stroke="Black"
                     StrokeDashArray="1 2"
                     Opacity="0" />
        </Border>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>
<Style x:Key="{x:Type TreeViewItem}"
       TargetType="{x:Type TreeViewItem}">
  <Setter Property="Background"
          Value="Transparent" />
  <Setter Property="HorizontalContentAlignment"
          Value="{Binding Path=HorizontalContentAlignment,
    RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" />
  <Setter Property="VerticalContentAlignment"
          Value="{Binding Path=VerticalContentAlignment,
    RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" />
  <Setter Property="Padding"
          Value="1,0,0,0" />
  <Setter Property="Foreground"
          Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
  <Setter Property="FocusVisualStyle"
          Value="{StaticResource TreeViewItemFocusVisual}" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type TreeViewItem}">
        <Grid>
          <Grid.ColumnDefinitions>
            <ColumnDefinition MinWidth="19"
                              Width="Auto" />
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="*" />
          </Grid.ColumnDefinitions>
          <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition />
          </Grid.RowDefinitions>
          <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="SelectionStates">
              <VisualState x:Name="Selected">
                <Storyboard>
                  <ColorAnimationUsingKeyFrames Storyboard.TargetName="Bd"
                                                Storyboard.TargetProperty="(Panel.Background).
                    (SolidColorBrush.Color)"
                                                >
                    <EasingColorKeyFrame KeyTime="0"
                                         Value="{StaticResource SelectedBackgroundColor}" />
                  </ColorAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
              <VisualState x:Name="Unselected" />
              <VisualState x:Name="SelectedInactive">
                <Storyboard>
                  <ColorAnimationUsingKeyFrames Storyboard.TargetName="Bd"
                                                Storyboard.TargetProperty="(Panel.Background).
                    (SolidColorBrush.Color)">
                    <EasingColorKeyFrame KeyTime="0"
                                         Value="{StaticResource SelectedUnfocusedColor}" />
                  </ColorAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
            </VisualStateGroup>
            <VisualStateGroup x:Name="ExpansionStates">
              <VisualState x:Name="Expanded">
                <Storyboard>
                  <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
                                                 Storyboard.TargetName="ItemsHost">
                    <DiscreteObjectKeyFrame KeyTime="0"
                                            Value="{x:Static Visibility.Visible}" />
                  </ObjectAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
              <VisualState x:Name="Collapsed" />
            </VisualStateGroup>
          </VisualStateManager.VisualStateGroups>
          <ToggleButton x:Name="Expander"
                        Style="{StaticResource ExpandCollapseToggleStyle}"
                        ClickMode="Press"
                        IsChecked="{Binding IsExpanded, 
            RelativeSource={RelativeSource TemplatedParent}}"/>
          <Border x:Name="Bd"
                  Grid.Column="1"
                  Background="{TemplateBinding Background}"
                  BorderBrush="{TemplateBinding BorderBrush}"
                  BorderThickness="{TemplateBinding BorderThickness}"
                  Padding="{TemplateBinding Padding}">
            <ContentPresenter x:Name="PART_Header"
                              ContentSource="Header"
                              HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
          </Border>
          <ItemsPresenter x:Name="ItemsHost"
                          Grid.Row="1"
                          Grid.Column="1"
                          Grid.ColumnSpan="2"
                          Visibility="Collapsed" />
        </Grid>
        <ControlTemplate.Triggers>
          <Trigger Property="HasItems"
                   Value="false">
            <Setter TargetName="Expander"
                    Property="Visibility"
                    Value="Hidden" />
          </Trigger>
          <MultiTrigger>
            <MultiTrigger.Conditions>
              <Condition Property="HasHeader"
                         Value="false" />
              <Condition Property="Width"
                         Value="Auto" />
            </MultiTrigger.Conditions>
            <Setter TargetName="PART_Header"
                    Property="MinWidth"
                    Value="75" />
          </MultiTrigger>
          <MultiTrigger>
            <MultiTrigger.Conditions>
              <Condition Property="HasHeader"
                         Value="false" />
              <Condition Property="Height"
                         Value="Auto" />
            </MultiTrigger.Conditions>
            <Setter TargetName="PART_Header"
                    Property="MinHeight"
                    Value="19" />
          </MultiTrigger>
        </ControlTemplate.Triggers>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

The preceding example uses one or more of the following resources.

<!--Control colors.-->
<Color x:Key="WindowColor">#FFE8EDF9</Color>
<Color x:Key="ContentAreaColorLight">#FFC5CBF9</Color>
<Color x:Key="ContentAreaColorDark">#FF7381F9</Color>

<Color x:Key="DisabledControlLightColor">#FFE8EDF9</Color>
<Color x:Key="DisabledControlDarkColor">#FFC5CBF9</Color>
<Color x:Key="DisabledForegroundColor">#FF888888</Color>

<Color x:Key="SelectedBackgroundColor">#FFC5CBF9</Color>
<Color x:Key="SelectedUnfocusedColor">#FFDDDDDD</Color>

<Color x:Key="ControlLightColor">White</Color>
<Color x:Key="ControlMediumColor">#FF7381F9</Color>
<Color x:Key="ControlDarkColor">#FF211AA9</Color>

<Color x:Key="ControlMouseOverColor">#FF3843C4</Color>
<Color x:Key="ControlPressedColor">#FF211AA9</Color>


<Color x:Key="GlyphColor">#FF444444</Color>
<Color x:Key="GlyphMouseOver">sc#1, 0.004391443, 0.002428215, 0.242281124</Color>

<!--Border colors-->
<Color x:Key="BorderLightColor">#FFCCCCCC</Color>
<Color x:Key="BorderMediumColor">#FF888888</Color>
<Color x:Key="BorderDarkColor">#FF444444</Color>

<Color x:Key="PressedBorderLightColor">#FF888888</Color>
<Color x:Key="PressedBorderDarkColor">#FF444444</Color>

<Color x:Key="DisabledBorderLightColor">#FFAAAAAA</Color>
<Color x:Key="DisabledBorderDarkColor">#FF888888</Color>

<Color x:Key="DefaultBorderBrushDarkColor">Black</Color>

<!--Control-specific resources.-->
<Color x:Key="HeaderTopColor">#FFC5CBF9</Color>
<Color x:Key="DatagridCurrentCellBorderColor">Black</Color>
<Color x:Key="SliderTrackDarkColor">#FFC5CBF9</Color>

<Color x:Key="NavButtonFrameColor">#FF3843C4</Color>

<LinearGradientBrush x:Key="MenuPopupBrush"
                     EndPoint="0.5,1"
                     StartPoint="0.5,0">
  <GradientStop Color="{DynamicResource ControlLightColor}"
                Offset="0" />
  <GradientStop Color="{DynamicResource ControlMediumColor}"
                Offset="0.5" />
  <GradientStop Color="{DynamicResource ControlLightColor}"
                Offset="1" />
</LinearGradientBrush>

<LinearGradientBrush x:Key="ProgressBarIndicatorAnimatedFill"
                     StartPoint="0,0"
                     EndPoint="1,0">
  <LinearGradientBrush.GradientStops>
    <GradientStopCollection>
      <GradientStop Color="#000000FF"
                    Offset="0" />
      <GradientStop Color="#600000FF"
                    Offset="0.4" />
      <GradientStop Color="#600000FF"
                    Offset="0.6" />
      <GradientStop Color="#000000FF"
                    Offset="1" />
    </GradientStopCollection>
  </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

For the complete sample, see Styling with ControlTemplates Sample.

See Also

Style
ControlTemplate
Control Styles and Templates
Control Customization
Styling and Templating
Customizing the Appearance of an Existing Control by Creating a ControlTemplate