<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" HorizontalAlignment="Center" VerticalAlignment="Center"> <Grid> <Grid.Triggers> <EventTrigger RoutedEvent="Grid.Loaded"> <BeginStoryboard> <Storyboard> <DoubleAnimation To="300" Duration="0:0:1" Storyboard.TargetName="left" Storyboard.TargetProperty="Width" /> </Storyboard> </BeginStoryboard> </EventTrigger> </Grid.Triggers> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition /> </Grid.ColumnDefinitions> <Ellipse Name="right" Grid.Column="1" Fill="Green" Width="100" Height="10" /> </Grid> </Page>