How to interchange items in grid view and how to get index of item where another item is dropped

I have a grid view canDrag and candrop are True and canReorder is False

Now i want to drag one item from gridview and drop it over another item in same gridview.

At that instance dragged item get placed there and item on which the dragged item was droped get placed at starting point 

In simple word i want to inter change two item in grid view but canreorder must be false

How can i do that