ArcGISWindowsPhoneSDK.Union.UnionButton_Click C# (CSharp) Method

        private void UnionButton_Click(object sender, RoutedEventArgs e)
        {
            UnionButton.IsEnabled = false;
            MyDrawObject.IsEnabled = false;

            GeometryService geometryService =
                        new GeometryService("http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
            geometryService.UnionCompleted += GeometryService_UnionCompleted;
            geometryService.Failed += GeometryService_Failed;

            geometryService.UnionAsync(selectedGraphics);
        }