如何使用依赖属性在两个WPF控件之间画一条线？

我有以下示例,但我无法让它工作.

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        Node node1 = new Node(myCanvas) { Width = 50,Height = 50 };
        Node node2 = new Node(myCanvas) { Width = 50,Height = 50 };

        Canvas.SetLeft(node1,0);
        Canvas.SetLeft(node2,200);

        Canvas.SetTop(node1,0);
        Canvas.SetTop(node2,0);

        myCanvas.Children.Add(node1);
        myCanvas.Children.Add(node2);

        Connector conn = new Connector();
        conn.Source = node1.AnchorPoint;
        conn.Destination = node2.AnchorPoint;

        myCanvas.Children.Add(conn);
    }
}

class Node : Control
{
    public static readonly DependencyProperty AnchorPointProperty =
        DependencyProperty.Register(
            "AnchorPoint",typeof(Point),typeof(Node),new FrameworkPropertyMetadata(new Point(0,0),FrameworkPropertyMetadataOptions.AffectsMeasure));

    public Point AnchorPoint
    {
        get { return (Point)GetValue(AnchorPointProperty); }
        set { SetValue(AnchorPointProperty,value); }
    }

    private Canvas mCanvas;

    public Node(Canvas canvas)
    {
        mCanvas = canvas;
        this.LayoutUpdated += Node_LayoutUpdated;
    }

    void Node_LayoutUpdated(object sender,EventArgs e)
    {
        Size size = RenderSize;
        Point ofs = new Point(size.Width / 2,size.Height / 2);
        AnchorPoint = TransformToVisual(this.mCanvas).Transform(ofs);
    }

    protected override void OnRender(DrawingContext drawingContext)
    {
        drawingContext.DrawEllipse(
            Brushes.Red,null,new Point(Width / 2,Height / 2),Width / 2,Height / 2);
    }
}

public sealed class Connector : UserControl
{
    public static readonly DependencyProperty SourceProperty =
        DependencyProperty.Register(
            "Source",typeof(Connector),new FrameworkPropertyMetadata(default(Point)));

    public Point Source {
        get { return (Point)this.GetValue(SourceProperty); }
        set { this.SetValue(SourceProperty,value); }
    }

    public static readonly DependencyProperty DestinationProperty =
        DependencyProperty.Register(
            "Destination",new FrameworkPropertyMetadata(default(Point)));

    public Point Destination {
        get { return (Point)this.GetValue(DestinationProperty); }
        set { this.SetValue(DestinationProperty,value); }
    }

    public Connector()
    {
        LineSegment segment = new LineSegment(default(Point),true);
        PathFigure figure = new PathFigure(default(Point),new[] { segment },false);
        PathGeometry geometry = new PathGeometry(new[] { figure });
        BindingBase sourceBinding = 
           new Binding { Source = this,Path = new PropertyPath(SourceProperty) };
        BindingBase destinationBinding = 
           new Binding { Source = this,Path = new PropertyPath(DestinationProperty) };
        BindingOperations.SetBinding(
            figure,PathFigure.StartPointProperty,sourceBinding);
        BindingOperations.SetBinding(
            segment,LineSegment.PointProperty,destinationBinding);
        Content = new Path
        {
            Data = geometry,StrokeThickness = 5,Stroke = Brushes.White,MinWidth = 1,MinHeight = 1
        };
    }
}