Mouse.GetPosition Method (IInputElement)
Gets the position of the mouse relative to a specified element.
Assembly: PresentationCore (in PresentationCore.dll)
The coordinate space in which to calculate the position of the mouse.
Return ValueType: System.Windows.Point
The position of the mouse relative to the parameter relativeTo.
The position of the mouse pointer is calculated relative to the specified element with the upper-left corner of element being the point of origin, 0,0.
During drag-and-drop operations, the position of the mouse cannot be reliably determined through. This is because control of the mouse (possibly including capture) is held by the originating element of the drag until the drop is completed, with much of the behavior controlled by underlying Win32 calls. Try the following approaches instead:
Available since 3.0