public static async Task<GoogleAPIAddressObj> ConvertAddressToLatLng(string address)
        {
            GoogleAPIAddressObj latLngObj = new GoogleAPIAddressObj();

            //GoogleAPIGeocoding URL
            string URL = ConstantVariable.googleAPIGeocodingAddressBaseURI
                + address
                + "&key="
                + ConstantVariable.googleGeolocationAPIkey;

            string json = await ReqAndRes.GetJsonString(URL);
            latLngObj = JsonConvert.DeserializeObject<GoogleAPIAddressObj>(json);

            return latLngObj;
        }
        private async void lls_OfficeAddress_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var selectedPlace = ((AutoCompletePlaceLLSObj)(sender as LongListSelector).SelectedItem);
            // If selected item is null, do nothing
            if (lls_OfficeAddress.SelectedItem == null)
            {
                return;
            }

            //show address on textbox
            GoogleAPIAddressObj address = new GoogleAPIAddressObj();
            address = await GoogleAPIFunction.ConvertAddressToLatLng(selectedPlace.Name.ToString());
            txt_OfficeAddress.Text = address.results[0].address_components[0].long_name.ToString()
                                + ", " + address.results[0].address_components[1].long_name.ToString()
                                + ", " + address.results[0].address_components[2].long_name.ToString();

            setCursorAtFirst(txt_OfficeAddress);

            SetOfficePositionFromAddress(address.results[0].formatted_address.ToString());

            //vibrate phone
            vibrateController.Start(TimeSpan.FromSeconds(0.1));

            HideLLSOfficeAddress();
        }
        private void proxy_SetOfficePositionFromAddress(object sender, DownloadStringCompletedEventArgs e)
        {
            //1. Convert chuối json lấy về thành object
            GoogleAPIAddressObj places = new GoogleAPIAddressObj();
            places = JsonConvert.DeserializeObject<GoogleAPIAddressObj>(e.Result);
            try
            {
                //Lấy tọa độ của điểm mới tìm được
                double lat = places.results[0].geometry.location.lat;
                double lng = places.results[0].geometry.location.lng;

                //Và dời vị trí map về đó
                map_OfficeAddress.SetView(new GeoCoordinate(lat, lng), 16, MapAnimationKind.Linear);

            }
            catch (Exception)
            {

                MessageBox.Show(ConstantVariable.errInvalidAddress);
            }
        }