Is it possible to create some sort of base expander style and override the background color of the header in a derived style? In my application I'm using expanders a lot and I would like to change the background color of the header. I know I could just copy&paste my style and edit the color, but it would be nicer to just create a new style based on the "base style" and setting the header's background color. But I do not know how to access this color. It's the color of this line: below I'd like to change (the border in the header): Border Name="border"... I cannot access "border" in the setter of the derived style...
This is my (base) style:
<Style TargetType="Expander" x:Key="ExpanderStyle">
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextColor}}"/>
<Setter Property="Template">
<Setter.Value>
<!-- Control template for expander -->
<ControlTemplate TargetType="Expander" x:Name="exp">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Name="ContentRow" Height="0"/>
</Grid.RowDefinitions>
<Border Name="border" Grid.Row="0" Background="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}" BorderThickness="1" CornerRadius="4,4,0,0" >
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="20" />
</Grid.ColumnDefinitions>
<ToggleButton x:Name="tb" FontFamily="Marlett" FontSize="9.75" Background="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}" Foreground="Black" Grid.Column="1" Content="u" IsChecked="{Binding Path=IsExpanded,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}" />
<ContentPresenter x:Name="HeaderContent" Grid.Column="0" Margin="4" ContentSource="Header" RecognizesAccessKey="True" />
</Grid>
</Border>
<Border x:Name="Content" Grid.Row="1" BorderThickness="1,0,1,1" CornerRadius="0,0,4,4" >
<ContentPresenter Margin="4" />
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="True">
<Setter TargetName="ContentRow" Property="Height" Value="{Binding ElementName=Content,Path=Height}" />
<Setter Property="Content" TargetName="tb" Value="t"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
I would like to do something like this:
<Style x:Key="ExpanderStyleRed" BasedOn="{StaticResource ExpanderStyle}" TargetType="Expander">
<Setter Property="???" Value="Red"/>
<Style>