使用Xamarin.forms.maps在iOS中的折线上放置图案

Question

我正在使用xamarin.forms.maps并成功获取折线，但我想在here上获得一些图案并且无法实现它。

任何人都可以帮我解决这个问题，我的代码如下：

formsMap.DrawPolyLine =（）=＆gt;

{

if（nativeMaps == null）

{

nativeMaps =控制为MKMapView;

}

nativeMaps.OverlayRenderer = GetOverlayRenderer;

                CLLocationCoordinate2D[] coords = new CLLocationCoordinate2D[IOSMapViewModel.DeviceTrackData.Count];
                int index = 0;
                foreach (var position in IOSMapViewModel.DeviceTrackData)
                {
                    coords[index] = new CLLocationCoordinate2D(position.Latitude, position.Longitude);
                    index++;
                }

                routeOverlay = MKGeodesicPolyline.FromCoordinates(coords);
                if (nativeMap.Overlays != null)
                    nativeMaps.RemoveOverlays(nativeMap.Overlays);
                IMKOverlay overlay = routeOverlay;

                nativeMaps.AddOverlay(routeOverlay, MKOverlayLevel.AboveLabels);
            };
            nativeMap.GetViewForAnnotation = GetViewForAnnotation;
            nativeMap.CalloutAccessoryControlTapped += OnCalloutAccessoryControlTapped;
        }
    }


    MKOverlayRenderer GetOverlayRenderer(MKMapView mapView, IMKOverlay overlayWrapper)
    {
        if (polylineRenderer == null && !Equals(overlayWrapper, null))
        {
            var overlay = Runtime.GetNSObject(overlayWrapper.Handle) as IMKOverlay;
            Foundation.NSNumber[] dashValues = { 3, 6 };
            polylineRenderer = new MKPolylineRenderer(overlay as MKGeodesicPolyline)
            {
                FillColor = UIColor.Orange,
                StrokeColor = UIColor.Orange,
                LineWidth = 3,
                Alpha = 1f,
                LineDashPattern = dashValues
            };
            //polylineRenderer.CreatePath();
        }
        return polylineRenderer;
    }