public override void OnApplyTemplate() { _leftThumb = base.GetTemplateChild("PART_LeftThumb") as Thumb ?? new Thumb(); _rightThumb = base.GetTemplateChild("PART_RightThumb") as Thumb ?? new Thumb(); _leftThumb.SetBinding(Canvas.LeftProperty, new Binding("LeftThumbPos") { Source = this }); _rightThumb.SetBinding(Canvas.RightProperty, new Binding("RightThumbPos") { Source = this }); _leftThumb.DragDelta += DragDeltaLeft; _rightThumb.DragDelta += DragDeltaRight; base.OnApplyTemplate(); }