DoDragDrop oddity with Right Mouse Button

Question

Hi all,
More experimentation - today with Drag & Drop.
Everything seems fine when performing this with the left mouse button, but when initiating this from WPF
with the right mouse button it appears to trigger the PreviewDrop event on the originating object.
I've tried intercepting QueryContinueDragHandler, which is fired and is having an Action set of Continue - all to no avail.
Much time with google shows no examples of people using the right mouse button with DoDragDrop, and a single query on this forum in September with someone having a similar problem.  No replies to that thread - hopeing for more luck today!
So, has anyone successfully initiated a system based Drag/Drop using the right mouse button?  In this case I'm working with a ListView, but I suspect that is fairly irrelevant.
Events occuring with Right Mouse Button depressed (and dragging a small way) are:
Call to: System.Windows.DragDrop.DoDragDrop
Callback: DropSource_ContinueDragEventHandler
Callback: DropTarget_PreviewDragEnter
Callback: DropSource_ContinueDragEventHandler
Callback: DropTarget_PreviewDrop
With the Left Mouse Button:
Call to: System.Windows.DragDrop.DoDragDrop
Callback: DropSource_ContinueDragEventHandler
Callback: DropTarget_PreviewDragEnter
Callback: DropSource_ContinueDragEventHandler
Callback: DropSource_ContinueDragEventHandler
Callback: DropSource_ContinueDragEventHandler
etc...
Anyone aware of any issues in this area?
Thanks,
Glyn
PS: The behaviour is different if dragging something from another application / desktop to a drop target, so it appears to be related to the originating side of things. ie, there is no problem when dragging an object from the desktop or similar.

Answer 1

Hmm - seem to have found the problem - it is related to the ContinueDragEventHandler!
Here is a suitable handler for dealing with Left & Right mouse button drags
You can activate it using:
DragDrop.AddQueryContinueDragHandler(this, QueryContinueDragHandler);
private void QueryContinueDragHandler(Object source, QueryContinueDragEventArgs e)
    e.Handled = true;       
    // Check if we need to bail
    if (e.EscapePressed)
        e.Action = DragAction.Cancel;       
        return;
    // Now, default to actually having dropped
    e.Action = DragAction.Drop;
    if ((e.KeyStates & DragDropKeyStates.LeftMouseButton) != DragDropKeyStates.None)
        // Still dragging with Left Mouse Button
        e.Action = DragAction.Continue;
    else if ((e.KeyStates & DragDropKeyStates.RightMouseButton) != DragDropKeyStates.None)
        // Still dragging with Right Mouse Button
        e.Action = DragAction.Continue;