using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.IO;
using System.Collections;

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        //API Credentials (3-token)
        string strUsername = "<<enter your sandbox username here>>";
        string strPassword = "<<enter your sandbox password here>>";
        string strSignature = "<<enter your signature here>>";
        string strCredentials = "USER=" + strUsername + "&PWD=" + strPassword + "&SIGNATURE=" + strSignature;

        string strNVPSandboxServer = "https://api-3t.sandbox.paypal.com/nvp";
        string strAPIVersion = "2.3";

        string strNVP = strCredentials + "&METHOD=DoDirectPayment" +
        "&CREDITCARDTYPE=" + "Visa" +
        "&ACCT=" + "4710496235600346" +
        "&EXPDATE=" + "10" + "2017" +
        "&CVV2=" + "123" +
        "&AMT=" + "12.34" +
        "&FIRSTNAME=" + "Demo" +
        "&LASTNAME=" + "User" +
        "&IPADDRESS=192.168.2.236" +
        "&STREET=" + "Lorem-1" +
        "&CITY=" + "Lipsum-1" +
        "&STATE=" + "Lorem" +
        "&COUNTRY=" + "INDIA" +
        "&ZIP=" + "302004" +
        "&COUNTRYCODE=IN" +
        "&PAYMENTACTION=Sale" +
        "&VERSION=" + strAPIVersion;

        try
        {
            //Create web request and web response objects, make sure you using the correct server (sandbox/live)
            HttpWebRequest wrWebRequest = (HttpWebRequest)WebRequest.Create(strNVPSandboxServer);
            wrWebRequest.Method = "POST";
            StreamWriter requestWriter = new StreamWriter(wrWebRequest.GetRequestStream());
            requestWriter.Write(strNVP);
            requestWriter.Close();

            // Get the response.
            HttpWebResponse hwrWebResponse = (HttpWebResponse)wrWebRequest.GetResponse();
            StreamReader responseReader = new StreamReader(wrWebRequest.GetResponse().GetResponseStream());

            //and read the response
            string responseData = responseReader.ReadToEnd();
            responseReader.Close();

            string result = Server.UrlDecode(responseData);

            string[] arrResult = result.Split('&');
            Hashtable htResponse = new Hashtable();
            string[] responseItemArray;
            foreach (string responseItem in arrResult)
            {
                responseItemArray = responseItem.Split('=');
                htResponse.Add(responseItemArray[0], responseItemArray[1]);
            }

            string strAck = htResponse["ACK"].ToString();

            if (strAck == "Success" || strAck == "SuccessWithWarning")
            {
                string strAmt = htResponse["AMT"].ToString();
                string strCcy = htResponse["CURRENCYCODE"].ToString();
                string strTransactionID = htResponse["TRANSACTIONID"].ToString();
                //ordersDataSource.InsertParameters["TransactionID"].DefaultValue = strTransactionID;

                string strSuccess = "Thank you, your order for: $" + strAmt + " " + strCcy + " has been processed.";
                //successLabel.Text = strSuccess;
                Response.Write(strSuccess.ToString());
            }
            else
            {
                string strErr = "Error: " + htResponse["L_LONGMESSAGE0"].ToString();
                string strErrcode = "Error code: " + htResponse["L_ERRORCODE0"].ToString();
                //errLabel.Text = strErr;
                //errcodeLabel.Text = strErrcode;
                Response.Write(strErr.ToString() + "<br/>" + strErrcode.ToString());
                return;
            }
        }
        catch (Exception ex)
        {
            // do something to catch the error, like write to a log file.
            Response.Write("error processing");
        }
    }
}