public static void Reverse(Esri.ArcGISRuntime.Geometry.PointCollection pts) { IEnumerable <MapPoint> reversedPts = pts.Reverse(); Esri.ArcGISRuntime.Geometry.PointCollection newPts = new Esri.ArcGISRuntime.Geometry.PointCollection(); foreach (MapPoint pt in reversedPts) { newPts.Add(pt); } pts.Clear(); foreach (MapPoint pt in newPts) { pts.Add(pt); } }