WPF Color Animation in SolidColorBrush

<Window x:Class="HowToSamples.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" Loaded="Window_Loaded">
    <StackPanel Margin="20" Name="LayoutRoot">
       <Rectangle Width="300" Height="200">
            <Rectangle.Fill>
                <SolidColorBrush x:Name="redBrush" Color="Red" />
            </Rectangle.Fill>
            <Rectangle.Triggers>
              <EventTrigger RoutedEvent="Rectangle.MouseEnter">
                    <BeginStoryboard>
                        <Storyboard>
                            <ColorAnimation Storyboard.TargetName="redBrush"
                            Storyboard.TargetProperty="Color" To="Green" Duration="0:0:1" />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>

                 <EventTrigger RoutedEvent="Rectangle.MouseLeave">
                    <BeginStoryboard>
                        <Storyboard>
                            <ColorAnimation Storyboard.TargetName="redBrush"
                            Storyboard.TargetProperty="Color" To="Red" Duration="0:0:1" />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>

                <EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Storyboard.TargetName="redBrush"
                                Storyboard.TargetProperty="Opacity" To="0.0" Duration="0:0:0.5"
                                             AutoReverse="True" />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </Rectangle.Triggers>
        </Rectangle>      
        
    </StackPanel>

</Window>

 private void ColorAnimationInredRectangle()
{
    // Create a Red SolidColorBrush 
    SolidColorBrush redBrush = new SolidColorBrush();
    redBrush.Color = Colors.Red;

    // Create a Rectangle filled with Red brush
    Rectangle redRectangle = new Rectangle();
    redRectangle.Width = 300;
    redRectangle.Height = 200;           
    redRectangle.Fill = redBrush;

    // Register the brush's name 
    this.RegisterName("redBrush", redBrush);

    // Animate brush with Green color 
    ColorAnimation mouseEnterColorAnimation = new ColorAnimation();
    mouseEnterColorAnimation.To = Colors.Green;
    mouseEnterColorAnimation.Duration = TimeSpan.FromSeconds(1);
    Storyboard.SetTargetName(mouseEnterColorAnimation, "redBrush");
    Storyboard.SetTargetProperty(
        mouseEnterColorAnimation, new PropertyPath(SolidColorBrush.ColorProperty));
    Storyboard mouseEnterStoryboard = new Storyboard();
    mouseEnterStoryboard.Children.Add(mouseEnterColorAnimation);
    redRectangle.MouseEnter += delegate(object sender, MouseEventArgs e)
    {
        mouseEnterStoryboard.Begin(this);
    };

    // Animate color back to red when mouse leaves
    ColorAnimation mouseLeaveColorAnimation = new ColorAnimation();
    mouseLeaveColorAnimation.To = Colors.Red;
    mouseLeaveColorAnimation.Duration = TimeSpan.FromSeconds(1);
    Storyboard.SetTargetName(mouseLeaveColorAnimation, "redBrush");
    Storyboard.SetTargetProperty(
        mouseLeaveColorAnimation, new PropertyPath(SolidColorBrush.ColorProperty));
    Storyboard mouseLeaveStoryboard = new Storyboard();
    mouseLeaveStoryboard.Children.Add(mouseLeaveColorAnimation);
    redRectangle.MouseLeave += delegate(object sender, MouseEventArgs e)
    {
        mouseLeaveStoryboard.Begin(this);
    };

    
    DoubleAnimation opacityAnimation = new DoubleAnimation();
    opacityAnimation.To = 0.0;
    opacityAnimation.Duration = TimeSpan.FromSeconds(0.5);
    opacityAnimation.AutoReverse = true;
    Storyboard.SetTargetName(opacityAnimation, "redBrush");
    Storyboard.SetTargetProperty(
        opacityAnimation, new PropertyPath(SolidColorBrush.OpacityProperty));
    Storyboard mouseLeftButtonDownStoryboard = new Storyboard();
    mouseLeftButtonDownStoryboard.Children.Add(opacityAnimation);
    redRectangle.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs e)
    {
        mouseLeftButtonDownStoryboard.Begin(this);
    };

    LayoutRoot.Children.Add(redRectangle);
}