In order to determine the real Y value, you need to know the amount that has been scrolled, which the scrollviewer can tell you.
You can obtain the scrollviewer as a child of the listview (Media.VisualTreeHelper.GetChild(Mylistview,0).Child
) , and from there the vertical offset it currently has (Scrollviewer.VerticalOffset
).
The vertical Offset does not give you the the y-coordinate-offset, instead you get the amount of listview-items scrolled down. You can easily work with that.