Authorized.Net And PayPal Express Gateway

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using ncMerchantGateway;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            //- Let's do 10 years of credit card expiration year.
            this.ddlExpYear.Items.Clear();
            this.ddlExpYear.Items.Add(new ListItem("SELECT", "0"));
            for (int i = 0; i <= 10; i++)
            {
                if (i > 0)
                {
                    this.ddlExpYear.Items.Add(new ListItem(DateTime.Now.AddYears(i).Year.ToString(), i.ToString()));
                }
            }
        }
    }
    protected void ddlPyamentMethod_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (ddlPaymentMethod.Text.Trim().ToUpper() == "PAYPAL")
        {
            PayPalExpress_Collect(sender, e);
        }
    }
    //---------------------------------------------------------------------------------
    //- Warning: a merchant account from authorized.net is required.
    //---------------------------------------------------------------------------------
    protected void AuthorizedDotNet_Collect(object sender, EventArgs e)
    {
        //- Entantiate the class here
        oAuthorizedotnet oGateway = new oAuthorizedotnet();

        //- very important information must be entered here
        oGateway.MerchantAccount_Version = "3.1"; // Authorized.net api version.
        oGateway.AccountHolder_LoginId = "valid login id goes here";
        oGateway.AccountHolder_TransactionKey = "valid merchant transaction key goes here";
        oGateway.AccountHolder_EMail = "merchart email registered with authorized.net goes here";
        oGateway.CompanyCollectorName = "ABC, Inc."; //- Merchant Company name goes here
        oGateway.AuthorizeChargesOnly = true; // Authorized Only (False = {Authorized and Capture})
        oGateway.Country = "USA";
        oGateway.Currency = "USD";
        oGateway.IsTestMode_Environment = false; //- Live

        //- Amount to be charged
        double dblCharges = 50.00;
        //- Sales Tax if there is any based on NYC sales tax.
        double dblSalesTax = (50.00 * 0.09);
        //- Total to Collect
        double dblTotalCharges = dblCharges + dblSalesTax;

        List<string> lstCCPaymentData = new List<string>();
        //- Please follow this order 0 throught 12
        lstCCPaymentData.Add("Jane"); //-Billing First-Name
        lstCCPaymentData.Add("Doe"); //-Billing Last-Name
        lstCCPaymentData.Add("123 Apple Road"); //-Billing Address
        lstCCPaymentData.Add("New York"); //-Billing City
        lstCCPaymentData.Add("NY"); //-Billing State
        lstCCPaymentData.Add("10040"); //-Billing Zipcode
        lstCCPaymentData.Add("212-555-5555"); //-Billing Telephone
        lstCCPaymentData.Add("[email protected]"); //-shipping email //-7

        //- Credit card info. exactly in this order.
        lstCCPaymentData.Add(this.txtCreditCardNumber.Text); //-Credit Card number
        lstCCPaymentData.Add(this.ddlExpMonth.Text); //- Credit card expiration month
        lstCCPaymentData.Add(this.ddlExpYear.Text); //-Credit card expiration year
        lstCCPaymentData.Add(this.txtSecurityCode.Text); //-Credit card security code
        lstCCPaymentData.Add(dblTotalCharges.ToString()); //-Total Amount to be either authorized or capture

        //- Connect with Authorize.net gateway now.
        oGateway.AuthorizeCaptureCharges(lstCCPaymentData);

        //- Return Message.(Display any error message returned from the Authorized.net gateway here)
        this.lblGatewayMessage.Text = oGateway.GatewayReturnedMessage.Trim();
    }
    //---------------------------------------------------------------------------------
    //- Warning: you must have a paypal account with valid email registered.
    //---------------------------------------------------------------------------------
    protected void PayPalExpress_Collect(object sender, EventArgs e)
    {

        //- Entantiate the class here
        oPayPalExpress oGateway = new oPayPalExpress();

        //- very important information must be entered here
        oGateway.ECommerce_SiteEMail = "[email protected]";
        oGateway.ECommerce_SiteUrl = "www.johndoe.com";
        oGateway.Country_Code = "US";
        oGateway.Currency_Code = "USD";
        oGateway.CancelledTransaction_Url = "http://www.johndoe.com/CancelledTransaction.html";
        oGateway.ReturnToECommerce_SiteUrl = "http://www.johndoe.com/Thankyou.html";

        //- Amount to be charged
        double dblCharges = 50.00;
        //- Pay Pal Fee if there is any [Warning: you must let the user know about this fee charges.]
        double dblProcessingFee = (dblCharges * 2.75) / 100;
        //- Sales Tax if there is any based on NYC sales tax.
        double dblSalesTax = (50.00 * 0.09);
        //- Total to Collect
        double dblTotalCharges = dblCharges + dblSalesTax + dblProcessingFee;

        List<string> lstPaymentInfo = new List<string>();
        //- Please follow this order
        lstPaymentInfo.Add("10012A"); //- Item Number
        lstPaymentInfo.Add("Tennis Shoes Size 10"); //- Item Description
        lstPaymentInfo.Add("1"); //- Qty goes here at least 1
        lstPaymentInfo.Add(dblTotalCharges.ToString()); //- Amount to charge goes here
        lstPaymentInfo.Add("20160813104523"); //- Invoice Number goes here
        lstPaymentInfo.Add(""); //- Shipping charges if any goes here otherwise blank
        lstPaymentInfo.Add(""); //- Handling charges if any goes here otherwise blank
        lstPaymentInfo.Add(dblSalesTax.ToString()); //- Sales Taxes if any goes here otherwise blank

        //- This part from here down is not necessary could all be blank ""
        lstPaymentInfo.Add("Jane"); //- First-name
        lstPaymentInfo.Add("Doe"); //- Last-name
        lstPaymentInfo.Add("123 Somewhere in the city"); //- Address
        lstPaymentInfo.Add("New York"); //- City
        lstPaymentInfo.Add("NY"); //- State
        lstPaymentInfo.Add("10005"); //- Zipcode
        lstPaymentInfo.Add("212-555-5555"); //- Telephone
        lstPaymentInfo.Add("[email protected]"); //- E-Mail

        //- Go to paypal now and collect
        oGateway.ProcessPayment(lstPaymentInfo);
    }
}