private async void LoadWebMap()
        {
            try
            {
                ArcGISPortal portal = new ArcGISPortal()
                {
                    Url = "http://www.arcgis.com/sharing/rest"
                };
                ArcGISPortalItem portalItem = new ArcGISPortalItem(portal)
                {
                    Id = "00e5e70929e14055ab686df16c842ec1"
                };

                WebMap webMap = await WebMap.FromPortalItemTaskAsync(portalItem);

                MyWebMapViewModel = await WebMapViewModel.LoadAsync(webMap, portalItem.ArcGISPortal);
            }
            catch (Exception ex)
            {
                if (ex is ServiceException)
                {
                    MessageBox.Show(String.Format("{0}: {1}", (ex as ServiceException).Code.ToString(), (ex as ServiceException).Details[0]), "Error", MessageBoxButton.OK);
                    return;
                }
            }
        }