<Window.Resources>
<SolidColorBrush x:Key="ButtonBrush" Color="OrangeRed" />
<Storyboard x:Key="ChangeBackgroundStoryboard">
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="ChangeBackgroundButton"
Storyboard.TargetProperty="Background">
<DiscreteObjectKeyFrame KeyTime="0:0:0"
Value="{StaticResource ButtonBrush}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</Window.Resources>
<Grid>
<Grid.Triggers>
<EventTrigger SourceName="ChangeBackgroundButton"
RoutedEvent="Button.Click">
<BeginStoryboard Storyboard="{StaticResource ChangeBackgroundStoryboard}" />
</EventTrigger>
</Grid.Triggers>
<Button Name="ChangeBackgroundButton"
Content="TestButton"
VerticalAlignment="Center"
HorizontalAlignment="Center" />
</Grid>