private void AddNewPaymentMethod(object sender, EventArgs e) { string userId = PaymentHelper.CreateNewCustomer(App.UserEmail); if (cardNumber.Text == "" || expiryMonth.Text == "" || expiryYear.Text == "" || cvv.Text == "") { DisplayAlert("Oops", "One or more fields have not been filled in", "Ok"); } else { try { PaymentHelper.AddNewPaymentOption(cardNumber.Text, Int32.Parse(expiryMonth.Text), Int32.Parse(expiryYear.Text), cvv.Text); } catch (Stripe.StripeException ex) { DisplayAlert("Oops", ex.Message, "Ok"); } } }