AnyPlace.MainPage.btn_poiscontrol_Click C# (CSharp) Method

        private void btn_poiscontrol_Click(object sender, RoutedEventArgs e)
        {
            var btn = sender as Button;
            var context = btn.DataContext as GeoCoordinate;

            if (Mymap.Layers.Contains(_sourceLayer))
                Mymap.Layers.Remove(_sourceLayer);

            _sourcePoi = false;
            _externalSource = true;
            _externalCoordinates = context;
            if (Mymap.MapElements.Contains(_polyline))
            {
                Mymap.MapElements.Remove(_polyline);
                NavigateToFloorPoi();
            }
            else
            {

                var imageMylocation = new Image
                {
                    Source = new BitmapImage(new Uri("/Assets/source.png", UriKind.Relative))
                };
                _sourceOverlay = new MapOverlay();
                _sourceLayer = new MapLayer();
                _sourceOverlay.Content = imageMylocation;
                _sourceOverlay.GeoCoordinate = context;
                _sourceOverlay.PositionOrigin = new Point(0.5, 1);
                _sourceLayer.Add(_sourceOverlay);
                Mymap.Layers.Add(_sourceLayer);
            }
        }