Xamarin.Android -coordinates from SQLite are not drawn on Google maps

I'm trying to implement Google maps markers using C#.I have lat/long values saved into my SQLite db which i then read and want to display on the map.There's an option on the action bar 'Load Points' that should call a method 'ReadPointsFromDb()' where i create the new Markers.i have tried a couple of examples with no difference,although drawing Markers on a map is pretty standard and i think I've done it correctly,except there's no effect when i click on Load points.Nothing changes.No markers are drawn on the map each time.

This is what the method looks like :

//retrieve a list of all the contents of receiverpoint table items
    public void ReadPointsFromDb()
    {


        double lat = 0;
        double lon = 0;

        int count = dataManager.GetAllReceiverPoints ().Count;

        foreach(ReceiverPointTable item in dataManager.GetAllReceiverPoints ())
        {
            lat = item.LATITUDE;

            lon = item.LONGITUDE;
        }

        if(map != null){



            RunOnUiThread (new Action (delegate {

                map.Clear ();

                receiver_point = new LatLng (lat, lon);

                var markerOpt1 = new MarkerOptions();
                markerOpt1.SetTitle("Test point");
                markerOpt1.SetPosition (receiver_point);
                markerOpt1.InvokeIcon(BitmapDescriptorFactory.DefaultMarker(BitmapDescriptorFactory.HueMagenta));
                map.AddMarker(markerOpt1);
            }));

        }

    }