在多个步骤中使用WPF设置关键帧动画

<Window x:Class="WpfApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Rectangle x:Name="myRectangle" Width="100" Height="100" Fill="Blue">
            <Rectangle.Triggers>
                <EventTrigger RoutedEvent="Rectangle.MouseDown">
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(Canvas.Left)">
                                <LinearDoubleKeyFrame Value="0" KeyTime="0:0:0"/>
                                <LinearDoubleKeyFrame Value="200" KeyTime="0:0:2"/>
                                <LinearDoubleKeyFrame Value="0" KeyTime="0:0:4"/>
                            </DoubleAnimationUsingKeyFrames>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </Rectangle.Triggers>
        </Rectangle>
    </Grid>
</Window>