关键代码部分

double[] lats = new double[] {

34.236995919519,34.237350707418 ,34.237989321866};

            double[] lons = new double[] {

108.881978988647,108.872194290161,108.842668533325};

            MKMapPoint[] pointArr=new MKMapPoint[lats.Length];

            for (int i = 0; i < lats.Length; i++) {

                CLLocationCoordinate2D coordinate =new CLLocationCoordinate2D(lats[i],lons[i]);

                MKMapPoint mPoint = MKMapPoint.FromCoordinate (coordinate);

                pointArr [i] = mPoint;

            }

            

            RoteLine = MKPolyline.FromPoints (pointArr); 

            mymapview.AddOverlay (RoteLine);

            mymapview.Delegate = new MyOverlayViewDelegate (this); 

 

　　　　 public MKPolyline RoteLine;

        public MKPolylineView RouteLineView;

        class MyOverlayViewDelegate:MKMapViewDelegate{

            MKOverlayView overlayView = null;

            MapViewController controller;

            public MyOverlayViewDelegate(MapViewController c){

                controller=c;

            }

            public override MKOverlayView GetViewForOverlay (MKMapView mapView, NSObject overlay)

            {

                if (overlay ==controller.RoteLine) {

                    if (controller.RouteLineView == null) {

                        controller.RouteLineView = new MKPolylineView (controller.RoteLine);

                        controller.RouteLineView.FillColor = UIColor.Red;

                        controller.RouteLineView.StrokeColor = UIColor.Red;

                        controller.RouteLineView.LineWidth = 3;

                    }

                    overlayView = controller.RouteLineView;

                }

                return overlayView; 

            }

            

        }