AnnotationDragDeltaEventArgs to Axis coordinates

Hello,

I’m trying to drag several VerticalLineAnnotationViewModel simultaneously. So if I drag one all other should move the same delta.
I subscribed the “DragDelta”-Event for each VerticalLineAnnotationViewModel. My problem is that “AnnotationDragDeltaEventArgs” seems in pixel unit and I didn’t find a CoordinateCalculator for the NumericAxisViewModel. Is there any solution to convert the dragged delta to dataValue or axis coordinates so I could just add the delta to the X1 property of my VerticalLineAnnotationViewModels?