public MapView ActivatedMapView {get;}

{
  //The active view must be a layout view.
  var lv = LayoutView.Active;
  if (lv == null)
    return;

  var map_view = lv.ActivatedMapView;
  if (map_view != null)
  {
    //TODO - use activated map view
  }
  var map_frame = lv.ActivatedMapFrame;
  if (map_frame != null)
  {
    //TODO - use activated map frame
  }
}