As a reference, I'm going to add what I replied to the topic starter by mail - just in case anyone else has the same question :-)
"All you need to do to start using it is referencing the Drag Drop assembly in your Silverlight project. From that moment on, you can use the DragSource and DropTarget controls in your projects (as
far as I know, you should be able to add them to the toolbox by dragging the assembly to it, but I never really tried it that way).
After you’ve added a reference to the assembly in your project, you can use them like this:
In code behind:
Import the namespace by adding a “using” directive to the top of your code behind file to import the drag drop namespace
Now you can use them just as you would use any control, eg: “DragSource myDragSource = new DragSource()” et cetera
Import the namespace by adding a “xmlns:dragdrop=”thedragdropassembly”” statement to the top of your UserControl
Now you can use them just as you would use any control, eg: “<DropTarget x:Name=”myDropTarget” …> </DropTarget>”
One of the easiest ways to learn how to use these controls is by having a look at the sample application – source code for this is included in the source code download.
Hope this helps!