Name cannot Found InvalidOperationException

Im getting Exception that name of ellipse which is dynamically set is not found while setting StoryBoard.TargetName of DoubleAnimation....
I already have StoryBoard in my XAML...

    public partial class MainWindow : Window
    {
        public List<double> starPoints = new List<double>();

        public MainWindow()
        {
            InitializeComponent();
            

        }

        public void CreateRandomStars()
        {
            
            int Width = (int)MyCanvas.Width;
            int Height = (int)MyCanvas.Height;
            
            
            Random Rnx = new Random(0);
            
            for (int i = 0; i < 300; i++)
            {                

                double Lx = (double)Rnx.Next(Width);
                double Ty = (double)Rnx.Next(Height);
                starPoints.Add(Ty);
                Ellipse es = new Ellipse();
                es.Name = "es_" + i.ToString();
                es.Width = 2;
                es.Height = 2;

                es.Fill = Brushes.WhiteSmoke;
                es.SetValue(Canvas.LeftProperty, Lx);
                es.SetValue(Canvas.TopProperty, Ty);
                
                MyCanvas.Children.Add(es);

                DoubleAnimation dAnim = new DoubleAnimation();
                dAnim.From = Ty;
                dAnim.To = Height;
                dAnim.Duration = new Duration(new TimeSpan(0, 0, 5));
                dAnim.SetValue(Storyboard.TargetNameProperty, es.Name);  //here the error is, Name cannot be found in Canvas...
                dAnim.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath(Canvas.TopProperty));

                MyStoryBoard.Children.Add(dAnim);
                
            }

         
        }

        private void MyCanvas_Loaded(object sender, RoutedEventArgs e)
        {
            CreateRandomStars();
        }

This is XAML.....

<Canvas Name="MyCanvas" Background="Black" Height="310" Width="500">
        <Canvas.Triggers>
            <EventTrigger RoutedEvent="Canvas.Loaded">
                <BeginStoryboard>
                    <Storyboard RepeatBehavior="Forever" Name="MyStoryBoard">
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Canvas.Triggers>
    </Canvas>

{"'es_0' name cannot be found in the name scope of 'System.Windows.Controls.Canvas'."}
This is the error...
Thnx!