if (CountryPhoneCode.SelectedItem != null)
            {
                var id = Guid.NewGuid().ToString("N");
                var countryPhoneCode = (CountryPhoneCode.SelectedItem as Country).PhoneCode;
                var name = FullName.Text;
                var phoneNumber = PhoneNumber.Text;
                var password = Password.Password;

                var client = new HttpClient()
                {
                    BaseAddress=new Uri("http://bedirhans.azurewebsites.net/chat/")
                };

                var json = await client.GetStringAsync("createUser?id=" + id + "&fullName" + name + "&phoneNumner" + phoneNumber + "");
                var serializer = new DataContractJsonSerializer(typeof(User));
                var ms = new MemoryStream();
                var user = serializer.ReadObject(ms) as User;

                Frame.Navigate(typeof(MainPage), user);
            }
            else {
                MessageDialog dialog = new MessageDialog("lütfen ülke seçiniz");
               await dialog.ShowAsync();
            }
        }