Question

I have two buttons, and need to link them with a line.
I bind the Line coordinates to the button positions.

I need to add this binding by code.

In XAML this work very well like this:

<Button x:Name="button1" Width="10" Height="10" Canvas.Left="150"  Canvas.Top="150"/>
<Button x:Name="button2" Width="10" Height="10" Canvas.Left="250"  Canvas.Top="100"/>

<Line x:Name="testLine" Stroke="Black"
      X1="{Binding ElementName=button1, Path=(Canvas.Left)}"
      Y1="{Binding ElementName=button1, Path=(Canvas.Top)}"
      X2="{Binding ElementName=button2, Path=(Canvas.Left)}"
      Y2="{Binding ElementName=button2, Path=(Canvas.Top)}"/>

Now, in code, I tried:

    Binding b = new Binding("(Canvas.Left)");
    b.ElementName = "button1";
    testLine.SetBinding(System.Windows.Shapes.Line.X1Property, "(Canvas.Left)");

but this does not work… (

EDIT :

There is one problem when creating dynamically the element:

Button button1 = new Button();
Canvas.SetLeft(button1, 50);
Canvas.SetTop(button1, 50);
button1.Name = "be1";
mainCanvas.Children.Add(button1);

Button button2 = new Button();
Canvas.SetLeft(button2, 150);
Canvas.SetTop(button2, 150);
button2.Name = "be2";
mainCanvas.Children.Add(button2);

Binding b1 = new Binding() { ElementName = "be1", Path = new PropertyPath("(Canvas.Left)") };
Binding b2 = new Binding() { ElementName = "be2", Path = new PropertyPath("(Canvas.Left)") };

testLine.SetBinding(System.Windows.Shapes.Line.X1Property, b1);
testLine.SetBinding(System.Windows.Shapes.Line.X2Property, b2);

It seems that “be1” does not exist or I don’t know what…

button1.RegisterName(button1.Name, button1); //does not help, error...

Answer 1

Are you sure you did not mean:

    Binding b = new Binding("(Canvas.Left)");
    b.ElementName = "button1";
    testLine.SetBinding(System.Windows.Shapes.Line.X1Property, b);

EDIT:

You shouldnt need the element name at all:

Button button1 = new Button();
Canvas.SetLeft(button1, 50);
Canvas.SetTop(button1, 50);
mainCanvas.Children.Add(button1);

Button button2 = new Button();
Canvas.SetLeft(button2, 150);
Canvas.SetTop(button2, 150);
mainCanvas.Children.Add(button2);

//juse Source reference not ElementName
Binding b1 = new Binding() { Source = button1, Path = new PropertyPath("(Canvas.Left)") };
Binding b2 = new Binding() { Source = button2, Path = new PropertyPath("(Canvas.Left)") };

testLine.SetBinding(System.Windows.Shapes.Line.X1Property, b1);
testLine.SetBinding(System.Windows.Shapes.Line.X2Property, b2);