Drag a WPF thumbnail on to target WPF listview

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C#

WPF

Firstly,please view this question from a tester's perspective.i will put down the question below:
1.I need to drag and drop a WPF FrameworkElement (a Thumbnail to be precise) to another WPF FrameworkElement (a ListView).
2.I don't want to use the X,Y co-ordinates for the target , as because if the resolution changes my test script will fail.
3.The source element is placed on A grid and target element on B grid and both A&B are placed on the same ContentPresenter.

The issue is, when I am trying to do a DragTo on the source element to the target element, I get a Null reference exception, probably the same reference doesn't work on the other grid.

What I have tried:

This is what I have tried to do:
sourceElement.User.DragTo((FrameworkElement)targetElement);

I am trying to use the InputSimulator for the MouseEvents but nothing much helping as they want UITesTControl as the elements. i was not able to cast a WPF element to a UItestControl element.
Please help me here.