Animate Width and Height of a Rectangle
<Window x:Class="Main" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="" Height="300" Width="300"> <Window.Resources> <Storyboard x:Key="rect1Storyboard" Storyboard.TargetName="rect1"> <ParallelTimeline> <DoubleAnimation To="50" Duration="0:0:10" FillBehavior="Stop" Storyboard.TargetProperty="Width" /> <DoubleAnimation To="50" Duration="0:0:5" FillBehavior="HoldEnd" AccelerationRatio="0.5" DecelerationRatio="0.25" Storyboard.TargetProperty="Height" /> </ParallelTimeline> </Storyboard> </Window.Resources> <Window.Triggers> <EventTrigger RoutedEvent="Rectangle.Loaded" SourceName="rect1"> <BeginStoryboard Storyboard="{StaticResource rect1Storyboard}" /> </EventTrigger> </Window.Triggers> <Grid> <Rectangle x:Name="rect1" Margin="10" Width="100" Height="100" Fill="Firebrick" Grid.Column="1" /> </Grid> </Window>