ArcGISWindowsPhoneSDK.BingImagery.LoadMapButton_Click C# (CSharp) Метод

        private void LoadMapButton_Click(object sender, RoutedEventArgs e)
        {
            WebClient webClient = new WebClient();
            string uri = string.Format("http://dev.virtualearth.net/REST/v1/Imagery/Metadata/Aerial?supressStatus=true&key={0}", BingKeyTextBox.Text);

            webClient.OpenReadCompleted += (s, a) =>
            {
                if (a.Error == null)
                {
                    DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(BingAuthentication));
                    BingAuthentication bingAuthentication = serializer.ReadObject(a.Result) as BingAuthentication;
                    a.Result.Close();

                    if (bingAuthentication.authenticationResultCode == "ValidCredentials")
                    {
                        ESRI.ArcGIS.Client.Bing.TileLayer tileLayer = new TileLayer()
                        {
                            ID = "BingLayer",
                            LayerStyle = TileLayer.LayerType.Road,
                            ServerType = ServerType.Production,
                            Token = BingKeyTextBox.Text
                        };

                        MyMap.Layers.Insert(0, tileLayer);

                        BingKeyGrid.Visibility = System.Windows.Visibility.Collapsed;
                        InvalidBingKeyTextBlock.Visibility = System.Windows.Visibility.Collapsed;
                    }
                    else InvalidBingKeyTextBlock.Visibility = System.Windows.Visibility.Visible;
                }
                else InvalidBingKeyTextBlock.Visibility = System.Windows.Visibility.Visible;
            };

            webClient.OpenReadAsync(new System.Uri(uri));
        }