public partial class AddAnInMemoryMarkerOverlay : UserControl
    {
        public AddAnInMemoryMarkerOverlay()
        {
            InitializeComponent();
        }

        private void WpfMap_Loaded(object sender, RoutedEventArgs e)
        {
            wpfMap1.MapUnit = GeographyUnit.DecimalDegree;
            wpfMap1.CurrentExtent = new RectangleShape(-155.733, 95.60, 104.42, -81.9);

            WorldMapKitWmsWpfOverlay worldMapKitOverlay = new WorldMapKitWmsWpfOverlay();
            wpfMap1.Overlays.Add(worldMapKitOverlay);

            InMemoryMarkerOverlay markerOverlay = new InMemoryMarkerOverlay();
            markerOverlay.Columns.Add(new FeatureSourceColumn("Name"));
            markerOverlay.ZoomLevelSet.ZoomLevel01.DefaultPointMarkerStyle.ImageSource = new BitmapImage(new Uri("/Resources/AQUA.png", UriKind.RelativeOrAbsolute));
            markerOverlay.ZoomLevelSet.ZoomLevel01.DefaultPointMarkerStyle.Width = 20;
            markerOverlay.ZoomLevelSet.ZoomLevel01.DefaultPointMarkerStyle.Height = 34;
            markerOverlay.ZoomLevelSet.ZoomLevel01.DefaultPointMarkerStyle.YScreenOffset = -17;
            markerOverlay.ZoomLevelSet.ZoomLevel01.DefaultPointMarkerStyle.ToolTip = "This is [#Name#].";
            markerOverlay.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
            wpfMap1.Overlays.Add("MarkerOverlay", markerOverlay);

            markerOverlay.FeatureSource.BeginTransaction();
            Random random = new Random();
            for (int i = 0; i < 30; i++)
            {
                Feature newFeature = new Feature(random.Next(-180, 180), random.Next(-90, 90));
                newFeature.ColumnValues.Add("Name", "Lawrence");
                markerOverlay.FeatureSource.AddFeature(newFeature);
            }
            markerOverlay.FeatureSource.CommitTransaction();
            wpfMap1.Refresh();
        }

        private void Button1_Click(object sender, RoutedEventArgs e)
        {
            if (wpfMap1.Overlays.Contains("MarkerOverlay"))
            {
                wpfMap1.Overlays.Remove("MarkerOverlay");
            }
        }
    }