Asp.Net mvc paypal integration

<p>

       <%

        BuyNowButton myBuyNowButton = new BuyNowButton

        {

            BusinessEmailOrMerchantID = "[email protected]",

            ItemName = ViewData["Item Name"].ToString(),

            ItemNumber = "Scenery 123",

            Quantity = Convert.ToInt32(ViewData["Quantity"]),

            Amount = Convert.ToDecimal(ViewData["Price"]),

            DiscountRate = 55

        };

        myBuyNowButton.PayPalFormSubmission.PostDestination =

            FormSubmissionSettings.PostActionDestinations.PayPal_Sandbox;

        myBuyNowButton.PayPalIPN.Custom_IPN_Url = "~/SellingSingleItem/HandleIPN";

        myBuyNowButton.PayPalReturn.Custom_CompletedReturnURL = "~/SellingSingleItem/PayPalReturned";

        myBuyNowButton.PayPalDisplayPage.ShippingAddress =

            PayPalDisplayPageSettings.ShippingAddressOptions.ShippingAddressOptional;

        myBuyNowButton.PayPalDisplayPage.HeaderBorderColor = Color.Red;

        myBuyNowButton.PayPalDisplayPage.HeaderBgColor = Color.LightYellow;

        myBuyNowButton.PayPalDisplayPage.PayFlowBgColor = Color.LightSteelBlue;

        myBuyNowButton.PayPalDisplayPage.HeaderImageURL = "~/Content/images/SpiceLogicBanner.jpg";

        myBuyNowButton.GenerateEncryptedButton = true;

        myBuyNowButton.EncryptedButtonGeneration.CertificateId = "4YF8UM67EW";

        myBuyNowButton.EncryptedButtonGeneration.PKCS12Password = "gah24352hi";

        myBuyNowButton.EncryptedButtonGeneration.PayPalCertPath = "~/App_Data/paypal_cert_pem.txt";

        myBuyNowButton.EncryptedButtonGeneration.PKCS12CertPath = "~/App_Data/my-cert.p12";

        myBuyNowButton.AdditionalDataItems["Customer's Name"] = "James Paul";             

    %>

       <%= myBuyNowButton.RenderForMVC() %>

p>

Here is the Action method for PayPalReturn / PDT

        public ActionResult PayPalReturned()

        {

            PayPalReturnHandler myReturnHandler = new PayPalReturnHandler

            {

                PDTAuthenticationToken = "IoSLdmDHmJZ9K2K98vsv42SGSGXCB2DK",

                NotifySyncDestination = FormSubmissionSettings.PostActionDestinations.PayPal_Sandbox

            };

            BuyNowReturnedEventArgs returnedData = myReturnHandler.GetBuyNowDataForMVC();

            ViewData["pdtData"] = returnedData.PDT.ToString();

            string greetingMsg = string.Format("Hello [{0}] !", returnedData.AdditionalDataItems["Customer's Name"]);

            if (returnedData.IsPaymentCancelled)

            {

                ViewData["isPaymentCancelled"] = true;

                greetingMsg += " Sorry, payment is cancelled";

            }

            else

            {

                ViewData["txnId"] = returnedData.TransactionID;

                greetingMsg += "Thank you for the payment.";

                ViewData["pdtStatus"] = returnedData.PDT.Status;

                ViewData["isPaymentCancelled"] = false;

                if (returnedData.PDT.Status == PayPalPDT.StatusCodes.SUCCESS)

                {

                    ViewData["item_name"] = returnedData.ItemInfo.ItemName;

                    ViewData["item_number"] = returnedData.ItemInfo.ItemNumber;

                    ViewData["paid_amount"] = returnedData.PaymentInfo.McGross;

                    ViewData["quantity"] = returnedData.ItemInfo.Quantity;

                    ViewData["buyerLastName"] = returnedData.BuyerInfo.LastName;

                    ViewData["addressCity"] = returnedData.BuyerInfo.ShippingAddress.City;

                    ViewData["charset"] = returnedData.CharSet;

                    ViewData["paymentStatus"] = returnedData.PaymentInfo.PaymentStatus;

                    ViewData["discount"] = returnedData.PaymentInfo.DiscountAmount;

                }

            }

            ViewData["returnMessage"] = greetingMsg;

            return View();

        }