Wpf change the background colour of an expander's header only - wpf

Question

I have looked at many questions/answers but couldn't find what I was exactly looking for,
I am trying to change the background colour of the expander's header only and not have the same colour continue for the content within the expander. Preferably within xaml but a vb.net solution would suffice.
(Any comments or suggestions will be helpful)
If this is a duplicated question please direct me to the answer and leave the question open to help others avoid the same issue in the future!
Thanks.

Answer 1

I am not sure whether this is what you are exactly looking for, but you could change the header background by simply doing that:
<Expander VerticalAlignment="Center">
<Expander.Header>
<Grid Background="LightBlue">
<TextBlock Text="Expander Header"/>
</Grid>
</Expander.Header>
<StackPanel>
<TextBlock Text="Cotent"></TextBlock>
</StackPanel>
</Expander>
Or you could override the default Expander's Header DataTemplate by using HeaderTemplate
<Window.Resources>
<DataTemplate x:Key="HeaderText">
<Border Height="25" Background="LightBlue">
<TextBlock Text="{Binding}"
Margin="4 0"
VerticalAlignment="Center"
Foreground="White"
FontSize="11"
FontWeight="Normal"
/>
</Border>
</DataTemplate>
<Style TargetType="{x:Type Expander}">
<Setter Property="HeaderTemplate" Value="{StaticResource HeaderText}"/>
</Style>
</Window.Resources>
<Grid x:Name="LayoutRoot">
<Expander VerticalAlignment="Center" Header="Expander Header">
<StackPanel>
<TextBlock Text="Cotent"></TextBlock>
</StackPanel>
</Expander>
</Grid>

Answer 2

I had a lot of problems with getting the header background set.
I found the easiets weay to do it was to simply make a coloured rectangle and put it behind the expander. (use Margin and Height to make it fit)
<Rectangle Grid.Row="1" Grid.Column="0" Fill="LightBlue" Height="33" Margin="0,0,0,-35" />
or use a border if you want rounded corners:
<Border CornerRadius="15" Height="33" Margin="0,0,0,-35" Background="LightBlue" />