WPF trigger animation from code

public static class AnimationHelper
{
    private static void AnimateOpacity(DependencyObject target, double from, double to)
    {
        var opacityAnimation = new DoubleAnimation
        {
            From = from,
            To = to,
            Duration = TimeSpan.FromMilliseconds(500)
        };

        Storyboard.SetTarget(opacityAnimation, target);
        Storyboard.SetTargetProperty(opacityAnimation, "Opacity");

        var storyboard = new Storyboard();
        storyboard.Children.Add(opacityAnimation);
        storyboard.Begin();
    }

    /// <summary>
    /// Fades in the given dependency object.
    /// </summary>
    /// <param name="target">The target dependency object to fade in.</param>
    public static void FadeIn(DependencyObject target)
    {
        AnimateOpacity(target, 0, 1);
    }
}

You can access storyboards from code-behind by giving it a name and referencing that name to use the Begin method.

<Canvas MouseLeftButtonDown="Handle_MouseDown"
  Background="Gray" Width="600" Height="500">
    <Canvas.Resources>
      <Storyboard x:Name="myStoryboard">
        <PointAnimation
          x:Name="myPointAnimation"
          Storyboard.TargetProperty="Center"
          Storyboard.TargetName="MyAnimatedEllipseGeometry"
          Duration="0:0:2"/>
      </Storyboard>
    </Canvas.Resources>

    <Path Fill="Blue">
      <Path.Data>
        <EllipseGeometry x:Name="MyAnimatedEllipseGeometry"
         Center="200,100" RadiusX="15" RadiusY="15" />
      </Path.Data>
    </Path>

</Canvas>

Code-behind:

private void Handle_MouseDown(object sender, MouseButtonEventArgs e)
{
    // Retrieve current mouse coordinates.
    double newX = e.GetPosition(null).X;
    double newY = e.GetPosition(null).Y;
    Point myPoint = new Point();
    myPoint.X = newX;
    myPoint.Y = newY;
    myPointAnimation.To = myPoint;
    myStoryboard.Begin();
}