Currently the WPF RadTreeView does not support built-in corss-control DragDrop. We are planning to include out Dragdrop framework in WPF to simplify this, but in the meantime you can use the WPF default DragDrop.
It revolves around adding handlers for the events of the DragDrop class. There are 12 events that handle starting, continuing and finishing a DragDrop operation.
You can read more about it in these MSDN articles:
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