Converting WGS84 Point to Maps Current Spatial Reference

JeffSmith3

I need to convert a WGS84 Lat/Lon point to my MapServices Spatial Reference. In this case, it happens to be Nad83.
Is there a typesafe way to convert a lat/lon point that I am receiving into whatever spatial reference my program is currently grabbing from the MapService it is looking at?
What libraries should I be looking at? Any examples would be great. Thank you.

JeffSmith3

In this case I am creating a new WGS84 Map Point, and trying to plot it on a Nad83 Spatial Ref.

           

            double lat = message.Latitude;
            double lon = message.Longitude;

            MapPoint mp = new MapPoint(lon, lat, new SpatialReference(4326));

            _pointLayer.Graphics.Clear();

            Graphic graphic = new Graphic()
            {
                Geometry = mp,
                Symbol = new SimpleMarkerSymbol() { Color = new SolidColorBrush(Colors.Blue), Size = 10 }
            };

            _pointLayer.Graphics.Add(graphic);

In this case _pointLayer is a Nad83 DynamicMapServiceLayer.
It throws an exception saying that the Graphic must match the SpatialRef of the service. Thanks again for the help.