protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                InMemoryFeatureLayer inmemoryFeatureLayer = new InMemoryFeatureLayer(); inmemoryFeatureLayer.Open();
                inmemoryFeatureLayer.Columns.Add(new FeatureSourceColumn("imageType"));

                ValueItem item1 = new ValueItem("image1", new PointStyle(new GeoImage(@"")));
                ValueItem item2 = new ValueItem("image2", new PointStyle(new GeoImage(@"")));

                ValueStyle valueStyle = new ValueStyle();
                valueStyle.ColumnName = "imageType";
                valueStyle.ValueItems.Add(item1);
                valueStyle.ValueItems.Add(item2);

                inmemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(valueStyle);
                inmemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

                Feature feature1 = new Feature(0,0);
                feature1.ColumnValues["imageType"] = "image1";
                Feature feature2 = new Feature(0,10);
                feature2.ColumnValues["imageType"] = "image2";

                inmemoryFeatureLayer.InternalFeatures.Add(feature1);
                inmemoryFeatureLayer.InternalFeatures.Add(feature2);

                LayerOverlay overLay = new LayerOverlay();
                overLay.Layers.Add("inmemoryFeatureLayer", inmemoryFeatureLayer);

                Map1.CurrentExtent = inmemoryFeatureLayer.GetBoundingBox();
                Map1.CurrentExtent = new RectangleShape(-180, 90, 180, -90);
                Map1.MapUnit = GeographyUnit.DecimalDegree;
                Map1.CustomOverlays.Add(overLay);
            }
        }