gistfile1.cs

        MyUserControl{
            InitializeComponent();
            Loaded +=  delegate {  StartAnimating(); };
        }


        public double StrokeValue
        {
            get { return (double)GetValue(StrokeValueProperty); }
            set { SetValue(StrokeValueProperty, value); }
        }

        public static readonly DependencyProperty StrokeValueProperty =
            DependencyProperty.Register("StrokeValue", typeof(double), typeof(SimplifyJoystick)
            , new PropertyMetadata(0.0, OnStrokeValueChanged));

        private static void OnStrokeValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            ((SimplifyJoystick)d).AnimatedStrokeArray = new DoubleCollection { (double)e.NewValue, 10000 };
        }


        public DoubleCollection AnimatedStrokeArray
        {
            get { return (DoubleCollection)GetValue(AnimatedStrokeArrayProperty); }
            set { SetValue(AnimatedStrokeArrayProperty, value); }
        }

        public static readonly DependencyProperty AnimatedStrokeArrayProperty =
            DependencyProperty.Register("AnimatedStrokeArray", typeof(DoubleCollection), typeof(SimplifyJoystick)
            , new PropertyMetadata(new DoubleCollection { 0, 100 }));
     

        private void StartAnimating()
        {
            var storyboard = new Storyboard() { RepeatBehavior = RepeatBehavior.Forever};
            var animation = new DoubleAnimation(0, ActualHeight * 4, new Duration(TimeSpan.FromSeconds(2)));
            storyboard.Children.Add(animation);
            Storyboard.SetTarget(animation, this);
            Storyboard.SetTargetProperty(animation, new PropertyPath(SimplifyJoystick.StrokeValueProperty));
            storyboard.Begin();
        }