ControlTemplate in WPF —— Expander

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">  <ResourceDictionary.MergedDictionaries>    <ResourceDictionary Source="Shared.xaml" />  </ResourceDictionary.MergedDictionaries>  <!-- SimpleStyles: Expander -->  <ControlTemplate x:Key="ExpanderToggleButton"                   TargetType="{x:Type ToggleButton}">    <Border x:Name="Border"            CornerRadius="2,0,0,0"            BorderThickness="0,0,1,0">      <Border.Background>        <LinearGradientBrush EndPoint="0.5,1"                             StartPoint="0.5,0">          <GradientStop Color="{DynamicResource ControlLightColor}" />          <GradientStop Color="{DynamicResource ControlMediumColor}"                        Offset="1" />        </LinearGradientBrush>      </Border.Background>      <Border.BorderBrush>        <LinearGradientBrush StartPoint="0,0"                             EndPoint="0,1">          <LinearGradientBrush.GradientStops>            <GradientStopCollection>              <GradientStop Color="{DynamicResource BorderLightColor}"                            Offset="0.0" />              <GradientStop Color="{DynamicResource BorderDarkColor}"                            Offset="1.0" />            </GradientStopCollection>          </LinearGradientBrush.GradientStops>        </LinearGradientBrush>      </Border.BorderBrush>      <VisualStateManager.VisualStateGroups>        <VisualStateGroup x:Name="CommonStates">          <VisualState x:Name="Normal" />          <VisualState x:Name="MouseOver">            <Storyboard>              <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"                                            Storyboard.TargetProperty="(Panel.Background).                  (GradientBrush.GradientStops)[1].(GradientStop.Color)">                <EasingColorKeyFrame KeyTime="0"                                     Value="{StaticResource ControlMouseOverColor}" />              </ColorAnimationUsingKeyFrames>            </Storyboard>          </VisualState>          <VisualState x:Name="Pressed">            <Storyboard>              <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"                                            Storyboard.TargetProperty="(Panel.Background).                  (GradientBrush.GradientStops)[1].(GradientStop.Color)">                <EasingColorKeyFrame KeyTime="0"                                     Value="{StaticResource ControlPressedColor}" />              </ColorAnimationUsingKeyFrames>            </Storyboard>          </VisualState>          <VisualState x:Name="Disabled">            <Storyboard>              <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"                                            Storyboard.TargetProperty="(Panel.Background).                  (GradientBrush.GradientStops)[1].(GradientStop.Color)">                <EasingColorKeyFrame KeyTime="0"                                     Value="{StaticResource DisabledControlDarkColor}" />              </ColorAnimationUsingKeyFrames>              <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"                                            Storyboard.TargetProperty="(Border.BorderBrush).                  (GradientBrush.GradientStops)[1].(GradientStop.Color)">                <EasingColorKeyFrame KeyTime="0"                                     Value="{StaticResource DisabledBorderLightColor}" />              </ColorAnimationUsingKeyFrames>            </Storyboard>          </VisualState>        </VisualStateGroup>        <VisualStateGroup x:Name="CheckStates">          <VisualState x:Name="Checked">            <Storyboard>              <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"                                             Storyboard.TargetName="CollapsedArrow">                <DiscreteObjectKeyFrame KeyTime="0"                                        Value="{x:Static Visibility.Hidden}" />              </ObjectAnimationUsingKeyFrames>              <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"                                             Storyboard.TargetName="ExpandededArrow">                <DiscreteObjectKeyFrame KeyTime="0"                                        Value="{x:Static Visibility.Visible}" />              </ObjectAnimationUsingKeyFrames>            </Storyboard>          </VisualState>          <VisualState x:Name="Unchecked" />          <VisualState x:Name="Indeterminate" />        </VisualStateGroup>      </VisualStateManager.VisualStateGroups>      <Grid>        <Path x:Name="CollapsedArrow"              HorizontalAlignment="Center"              VerticalAlignment="Center"              Data="M 0 0 L 4 4 L 8 0 Z">          <Path.Fill>            <SolidColorBrush Color="{DynamicResource GlyphColor}" />          </Path.Fill>        </Path>        <Path x:Name="ExpandededArrow"              HorizontalAlignment="Center"              VerticalAlignment="Center"              Visibility="Collapsed"              Data="M 0 4 L 4 0 L 8 4 Z">          <Path.Fill>            <SolidColorBrush Color="{DynamicResource GlyphColor}" />          </Path.Fill>        </Path>      </Grid>    </Border>  </ControlTemplate>  <Style TargetType="{x:Type Expander}">    <Setter Property="Template">      <Setter.Value>        <ControlTemplate TargetType="{x:Type Expander}">          <Grid>            <Grid.RowDefinitions>              <RowDefinition Height="Auto" />              <RowDefinition x:Name="ContentRow"                             Height="0" />            </Grid.RowDefinitions>            <VisualStateManager.VisualStateGroups>              <VisualStateGroup x:Name="CommonStates">                <VisualState x:Name="Normal" />                <VisualState x:Name="MouseOver" />                <VisualState x:Name="Disabled">                  <Storyboard>                    <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"                                                  Storyboard.TargetProperty="(Panel.Background).                        (GradientBrush.GradientStops)[1].(GradientStop.Color)">                      <EasingColorKeyFrame KeyTime="0"                                           Value="{StaticResource DisabledControlDarkColor}" />                    </ColorAnimationUsingKeyFrames>                    <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"                                                  Storyboard.TargetProperty="(Border.BorderBrush).                        (GradientBrush.GradientStops)[1].(GradientStop.Color)">                      <EasingColorKeyFrame KeyTime="0"                                           Value="{StaticResource DisabledBorderLightColor}" />                    </ColorAnimationUsingKeyFrames>                  </Storyboard>                </VisualState>              </VisualStateGroup>            </VisualStateManager.VisualStateGroups>            <Border x:Name="Border"                    Grid.Row="0"                    BorderThickness="1"                    CornerRadius="2,2,0,0">              <Border.BorderBrush>                <LinearGradientBrush EndPoint="0,1"                                     StartPoint="0,0">                  <GradientStop Color="{DynamicResource BorderLightColor}"                                Offset="0" />                  <GradientStop Color="{DynamicResource BorderDarkColor}"                                Offset="1" />                </LinearGradientBrush>              </Border.BorderBrush>              <Border.Background>                <LinearGradientBrush StartPoint="0,0"                                     EndPoint="0,1">                  <LinearGradientBrush.GradientStops>                    <GradientStopCollection>                      <GradientStop Color="{DynamicResource ControlLightColor}"                                    Offset="0.0" />                      <GradientStop Color="{DynamicResource ControlMediumColor}"                                    Offset="1.0" />                    </GradientStopCollection>                  </LinearGradientBrush.GradientStops>                </LinearGradientBrush>              </Border.Background>              <Grid>                <Grid.ColumnDefinitions>                  <ColumnDefinition Width="20" />                  <ColumnDefinition Width="*" />                </Grid.ColumnDefinitions>                <ToggleButton OverridesDefaultStyle="True"                              Template="{StaticResource ExpanderToggleButton}"                              IsChecked="{Binding IsExpanded, Mode=TwoWay,                     RelativeSource={RelativeSource TemplatedParent}}">                  <ToggleButton.Background>                    <LinearGradientBrush EndPoint="0.5,1"                                         StartPoint="0.5,0">                      <GradientStop Color="{DynamicResource ControlLightColor}"                                    Offset="0" />                      <GradientStop Color="{DynamicResource ControlMediumColor}"                                    Offset="1" />                    </LinearGradientBrush>                  </ToggleButton.Background>                </ToggleButton>                <ContentPresenter Grid.Column="1"                                  Margin="4"                                  ContentSource="Header"                                  RecognizesAccessKey="True" />              </Grid>            </Border>            <Border x:Name="Content"                    Grid.Row="1"                    BorderThickness="1,0,1,1"                    CornerRadius="0,0,2,2">              <Border.BorderBrush>                <SolidColorBrush Color="{DynamicResource BorderMediumColor}" />              </Border.BorderBrush>              <Border.Background>                <SolidColorBrush Color="{DynamicResource ContentAreaColorDark}" />              </Border.Background>              <ContentPresenter Margin="4" />            </Border>          </Grid>          <ControlTemplate.Triggers>            <Trigger Property="IsExpanded"                     Value="True">              <Setter TargetName="ContentRow"                      Property="Height"                      Value="{Binding DesiredHeight, ElementName=Content}" />            </Trigger>          </ControlTemplate.Triggers>        </ControlTemplate>      </Setter.Value>    </Setter>  </Style></ResourceDictionary>