Expander Styles and Templates
This topic describes the styles and templates for the Expander 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.
Expander Parts
The Expander control does not have any named parts.
Expander States
The following table lists the visual states for the Expander control.
VisualState Name |
VisualStateGroup Name |
Description |
Normal |
CommonStates |
The default state. |
MouseOver |
CommonStates |
The mouse pointer is positioned over the control. |
Disabled |
CommonStates |
The control is disabled. |
Focused |
FocusStates |
The control has focus. |
Unfocused |
FocusStates |
The control does not have focus. |
Expanded |
ExpansionStates |
The control is expanded. |
Collapsed |
ExpansionStates |
The control is not expanded. |
ExpandDown |
ExpandDirectionStates |
The control expands down. |
ExpandUp |
ExpandDirectionStates |
The control expands up. |
ExpandLeft |
ExpandDirectionStates |
The control expands left. |
ExpandRight |
ExpandDirectionStates |
The control expands right. |
Valid |
ValidationStates |
The control uses the Validation class and the Validation.HasError attached property is false. |
InvalidFocused |
ValidationStates |
The Validation.HasError attached property is true has the control has focus. |
InvalidUnfocused |
ValidationStates |
The Validation.HasError attached property is true has the control does not have focus. |
Expander ControlTemplate Example
The following example shows how to define a ControlTemplate for the Expander control.
<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>
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
Reference
Concepts
Customizing the Appearance of an Existing Control by Creating a ControlTemplate