Wie zeichnet man eine Linie zwischen zwei WPF-Steuerelementen mithilfe von Abhängigkeitseigenschaften?

Question

Ich muss eine Linie zeichnen, die zwei WPF Kontrollen verbindet. Ich habe eine Abhängigkeitseigenschaft in meinen Node Objekten so definiert, wenn der Knoten verschoben wird, verbindet die Linie noch die Objekte.

Ich habe das folgende Beispiel, aber ich kann es nicht funktionieren.

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(Point), 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", typeof(Point), typeof(Connector), 
       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 
     }; 
    } 
} 

Answer 1

Alles, was Sie tun müssen, um Ihr Beispiel Arbeit binden zuconn.Source und .Destination, um die Knoten zu machen Anchor oder auch der Connector erhält nur die Anchoranfangswerte (0,0), und hört nicht nach weiteren Änderungen:

... 

Connector conn = new Connector(); 
//conn.Source = node1.AnchorPoint; 
conn.SetBinding(Connector.SourceProperty, 
       new Binding() 
       { 
        Source = node1, 
        Path = new PropertyPath(Node.AnchorPointProperty) 
       }); 
//conn.Destination = node2.AnchorPoint; 
conn.SetBinding(Connector.DestinationProperty, 
       new Binding() 
       { 
        Source = node2, 
        Path = new PropertyPath(Node.AnchorPointProperty) 
       }); 

myCanvas.Children.Add(conn);