private async void btnSave_Click(object sender, RoutedEventArgs e) { LicenseDetailDto license = new LicenseDetailDto { SoftwareId = SoftwareId, Edition = txtEdition.Text, ActivationKey = txtActivationKey.Text, VolumeLicense = false }; bool?success; using (var client = new LicensesClient()) { success = await client.PostLicense(license); } if (success == null) { throw new NotImplementedException(); } if (!success.HasValue) { throw new NotImplementedException(); } if (!success.Value) { throw new NotImplementedException(); } this.Close(); }