WPF Drag and Drop Source Code

Question

Almost all the questions on stackoverflow dealing with drag and drop in WPF refer back to this article. However, the source code for the article is missing. Does anyone have a copy or know where to find a copy?

P.S. My main concern is this line from the article: "There is more code in DragAdorner, but mostly used for positioning the adorner as the drag is happening... please refer to the sample..." I have no idea how he positions the drag adorner.

There is a link on the page to email the blog author if you haven't already tried that. — Benjamin Gale, Jan 08 '13 at 21:23
I used that code. It was really buggy. You'll have to fix a lot of nuances if you want to make practical use. — Lee Louviere, Jan 14 '13 at 22:49

score 3 · Accepted Answer · answered Feb 11 '13 at 17:29

I have some working code based on the original series of blog posts. The full code is too long to post here; I've posted it to PasteBin.

The code in the DragAdorner is quite simple:

internal sealed class DragAdorner : Adorner
{
   private readonly UIElement _child;
   private readonly double _xCenter;
   private readonly double _yCenter;
   private double _leftOffset;
   private double _topOffset;

   public DragAdorner(UIElement owner, UIElement child, bool useVisualBrush, double opacity) : base(owner)
   {
      if (!useVisualBrush)
      {
         _child = child;
      }
      else
      {
         var size = GetRealSize(child);
         _xCenter = size.Width / 2;
         _yCenter = size.Height / 2;

         _child = new Rectangle
         {
            RadiusX = 3,
            RadiusY = 3,
            Width = size.Width,
            Height = size.Height,
            Fill = new VisualBrush(child)
            {
               Opacity = opacity,
               AlignmentX = AlignmentX.Left,
               AlignmentY = AlignmentY.Top,
               Stretch = Stretch.None,
            },
         };
      }
   }

   protected override int VisualChildrenCount
   {
      get { return 1; }
   }

   public double LeftOffset
   {
      get
      {
         return _leftOffset + _xCenter;
      }
      set
      {
         _leftOffset = value - _xCenter;
         UpdatePosition();
      }
   }

   public double TopOffset
   {
      get
      {
         return _topOffset + _yCenter;
      }
      set
      {
         _topOffset = value - _yCenter;
         UpdatePosition();
      }
   }

   private static Size GetRealSize(UIElement child)
   {
      return child == null ? Size.Empty : child.RenderSize;
   }

   public void UpdatePosition(Point point)
   {
      _leftOffset = point.X;
      _topOffset = point.Y;
      UpdatePosition();
   }

   public void UpdatePosition()
   {
      var adorner = Parent as AdornerLayer;
      if (adorner != null) adorner.Update(AdornedElement);
   }

   protected override Visual GetVisualChild(int index)
   {
      if (0 != index) throw new ArgumentOutOfRangeException("index");
      return _child;
   }

   protected override Size MeasureOverride(Size availableSize)
   {
      _child.Measure(availableSize);
      return _child.DesiredSize;
   }

   protected override Size ArrangeOverride(Size finalSize)
   {
      _child.Arrange(new Rect(_child.DesiredSize));
      return finalSize;
   }

   public override GeneralTransform GetDesiredTransform(GeneralTransform transform)
   {
      var result = new GeneralTransformGroup();
      result.Children.Add(new TranslateTransform(_leftOffset, _topOffset));

      var baseTransform = base.GetDesiredTransform(transform);
      if (baseTransform != null) result.Children.Add(baseTransform);

      return result;
   }
}

Nathan Hillyer · Answer 2 · 2013-10-20T21:05:02.977

1

E-mailed the author and got a response that he no longer has the source code for the article.

edited Oct 20 '13 at 21:05

answered Feb 11 '13 at 16:43

Nathan Hillyer

1,959
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I've got some working code based on the original article if you need it. – Richard Deeming Feb 11 '13 at 16:45
If it isn't too much trouble, that would be great! I managed to figure it out, but others may stumble across the question. – Nathan Hillyer Feb 11 '13 at 16:47

score 0 · Answer 3 · answered Jan 26 '13 at 22:34

0

check out bea stollnitz's blog

http://www.zagstudio.com/blog/488#.UQRZCL9fA7X

this drag and drop sample was one of the first ones back when WPF relatively new. It definitely helped me and my co-workers ...

answered Jan 26 '13 at 22:34

denis morozov

6,236
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Also down now. Article can be found on the Web Archive https://web.archive.org/web/20150912232819/http://www.zagstudio.com:80/blog/488#.WpnN2qjwa70 (Hopefully those web archive links are valid for a while) – FrankyB Mar 02 '18 at 22:22

WPF Drag and Drop Source Code

3 Answers3