Silverlight DragDropTarget - just copy, not move

I'd like to ask, how can I in Si开发者_StackOverflow中文版lverlight just copy an item with drag&drop, not move, if I'm using the DragDropTargets?

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I've fount that: Silverlight Toolkit Drag Drop (Part 2): Customizing Drag and Drop Behavior

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I guess you need to set the AllowedSourceEffects property for the source *DragDropTarget element, like here:

<toolkit:PanelDragDropTarget VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch" AllowedSourceEffects="Copy">
 <!-- here is a panel -->
</toolkit:PanelDragDropTarget>