How to integrate PayPal in ASP.NET?
In this article , I am going to explain about how to integrate PayPal in ASP.NET. Most of website Seller to get money from the buyer through PayPal. Here I have explained in detail each step with screen shot.
Description :
In this article I am going to deeply explain about PayPal integration, testing with Sandbox developer paypal account. Read carefully each steps then only able to understand PayPal integration
Here in this example I am used PayPal Sandbox site this is similar to live PayPal site. Sandbox is used to testing environment for developer provided by PayPal. After you tested just changed to Sandbox.Paypal.com to Paypal.com in PayPal Submit URL in web.config file that's all.
First I have create table like below to store purchaser detail
create table purchase(pname nvarchar(50),pdesc nvarchar(50),price nvarchar(50),uname nvarchar(50)) Create PayPal Account in SandBox to testing
Go to developer.paypal.com and create Paypal account to be testing
After create new account Login into the developer.paypal.com website. Now click on the Test accounts Right side and create two sub accounts
1) Buyer account
2) Seller account
After Click Preconfigured create account for buyer and seller like below
After enter all details click Create account button. Now those two accounts are displayed in your test accounts like Business, Personal 
That's fine now open visual studio and write coding to display product details and provide option to user buy our product through paypal.Client side
In client side I have displayed some product in grid view if user click that product buy button then redirect to PayPal sandox site
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Paypal Integartion</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table width="700" align="center" cellpadding="0" cellspacing="0">
<tr>
<td height="60">
<b>Paypal Integration in ASP.NET</b>
</td>
</tr>
<tr>
<td height="40" align="center">
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowCommand="GridView1_RowCommand"
BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px"
CellPadding="3">
<RowStyle ForeColor="#000066" />
<Columns>
<%-- <asp:TemplateField HeaderText="Product image">
<ItemTemplate>
<asp:Image ID="Image1" runat="server" Width="80" Height="60" ImageUrl='<%#Eval("path")%>' />
</ItemTemplate>
</asp:TemplateField>--%>
<asp:TemplateField HeaderText="Product Name">
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#Eval("pname") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Product Description">
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%#Eval("pdesc") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Product price">
<ItemTemplate>
<asp:Label ID="Label3" runat="server" Text='<%#Eval("price") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Buy Now">
<ItemTemplate>
<asp:ImageButton ID="ImageButton1" runat="server" ImageUrl="~/images/buyNow.png"
Width="80" Height="40" CommandName="buy" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
<FooterStyle BackColor="White" ForeColor="#000066" />
<PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" />
<SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" />
</asp:GridView>
</td>
</tr>
</table>
<!-- PayPal Logo -->
<table border="0" cellpadding="10" cellspacing="0" align="center">
<tr>
<td align="center">
</td>
</tr>
<tr>
<td align="center">
<a href="#" onclick="javascript:window.open('https://www.paypal.com/cgi-bin/webscr?cmd=xpt/Marketing/popup/OLCWhatIsPayPal-outside','olcwhatispaypal','toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes, resizable=yes, width=400, height=350');">
<img src="https://www.paypal.com/en_US/i/bnr/horizontal_solution_PPeCheck.gif" border="0"
alt="Solution Graphics"></a>
</td>
</tr>
</table>
<!-- PayPal Logo -->
</div>
</form>
</body>
</html>
Server side
In server side I collect which product user selected and send price, tax details to Paypal
using System.Data;
using System.Data.SqlClient;
using System.Data.OleDb;
using System.Configuration;
public partial class _Default : System.Web.UI.Page
{
SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["Con"].ToString());
SqlCommand sqlcmd = new SqlCommand();
SqlDataAdapter da = new SqlDataAdapter();
DataTable dt = new DataTable();
DataRow dr;
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
//Add some column to datatable display some products
dt.Columns.Add("pname");
dt.Columns.Add("pdesc");
dt.Columns.Add("price");
//Add rows with datatable and bind in the grid view
dr = dt.NewRow();
dr["pname"] = "Laptop";
dr["pdesc"] = "Professional laptop";
dr["price"] = "$100";
dt.Rows.Add(dr);
dr = dt.NewRow();
dr["pname"] = "Laptop";
dr["pdesc"] = "Personal Laptop";
dr["price"] = "$120";
dt.Rows.Add(dr);
dr = dt.NewRow();
dr["pname"] = "CPU";
dr["pdesc"] = "Comptuter accessories";
dr["price"] = "$40";
dt.Rows.Add(dr);
dr = dt.NewRow();
dr["pname"] = "Desktop";
dr["pdesc"] = "Home PC";
dr["price"] = "$150";
dt.Rows.Add(dr);
GridView1.DataSource = dt;
GridView1.DataBind();
}
}
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == "buy")
{
ImageButton ib = (ImageButton)e.CommandSource;
int index = Convert.ToInt32(ib.CommandArgument);
GridViewRow row = GridView1.Rows[index];
//Get each Column label value from grid view and store it in label
Label l1 = (Label)row.FindControl("Label1");
Label l2 = (Label)row.FindControl("Label2");
Label l3 = (Label)row.FindControl("Label3");
//here i temporary use my name as logged in user you can create login page after only make an order
Session["user"] = "ravi";
//After user clik buy now button store that details into the sql server "purchase" table for reference
string query = "";
query = "insert into purchase(pname,pdesc,price,uname) values('" + l1.Text + "','" + l2.Text + "','" + l3.Text.Replace("$","") + "','" + Session["user"].ToString() + "')";
sqlcon.Open();
sqlcmd = new SqlCommand(query, sqlcon);
sqlcmd.ExecuteNonQuery();
sqlcon.Close();
//Pay pal process Refer for what are the variable are need to send http://www.paypalobjects.com/IntegrationCenter/ic_std-variable-ref-buy-now.html
string redirecturl = "";
//Mention URL to redirect content to paypal site
redirecturl += "https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_xclick&business=" + ConfigurationManager.AppSettings["paypalemail"].ToString();
//First name i assign static based on login details assign this value
redirecturl += "&first_name=ravindran";
//City i assign static based on login user detail you change this value
redirecturl += "&city=chennai";
//State i assign static based on login user detail you change this value
redirecturl += "&state=tamilnadu";
//Product Name
redirecturl += "&item_name=" + l1.Text;
//Product Amount
redirecturl += "&amount=" + l3.Text;
//Business contact id
//redirecturl += "&business=nravindranmcaatgmail.com";
//Shipping charges if any
redirecturl += "&shipping=5";
//Handling charges if any
redirecturl += "&handling=5";
//Tax amount if any
redirecturl += "&tax=5";
//Add quatity i added one only statically
redirecturl += "&quantity=1";
//Currency code
redirecturl += "¤cy=USD";
//Success return page url
redirecturl += "&return=" + ConfigurationManager.AppSettings["SuccessURL"].ToString();
//Failed return page url
redirecturl += "&cancel_return=" + ConfigurationManager.AppSettings["FailedURL"].ToString();
Response.Redirect(redirecturl);
}
}
}
In web.config file I have set Return Url and PayPal business id etc. like below
<appSettings>
<add key ="token" value ="PW1BDVNqVPVanwduF_Tb2Ey91aT1Uhx1kL7HPc-7e8S-6AnUwSSHyasolSe"/>
<add key ="paypalemail" value ="nravin_1335778770_biz@gmail.com"/>
<!--Here i used sandbox site url only if you hosted in live change sandbox to live paypal URL-->
<add key="PayPalSubmitUrl" value="https://www.sandbox.paypal.com/cgi-bin/webscr"/>
<add key="FailedURL" value="http://localhost:2525/PayPalIntegration/Failed.aspx"/>
<add key="SuccessURL" value="http://localhost:2525/PayPalIntegration/Success.aspx"/>
</appSettings>
In the above url are local testing url after hosted in live changed your domain name in this values.
Web page is look like here
Steps to Execute Details Output
Make sure you are logged in the https://developer.paypal.com/ with your email id in the same browser during testing. Then only working fine to deduct amount etc. correctly. Only Sandbox site we must logged in developer site during testing but not in live paypal.com after hosted it
After user click Buy now in the gridview redirect to PayPal 
Now logged in to the Personal account mean Buyer account. After logged in display like below
Verify Details and click Paynow button. After that amount $ 55 USD deducted from your paypal personal account and increased $55 in seller account.
After click paynow confirmation show your transaction like below
After that automatically redirect to merchant site whatever URL you are configure in web.config file and insert transaction data in the table.
In the test account page select personal account radio button and then click enter sandbox site button below in that page to redirect personal account deails page
Below screen show Personal account detail after paid to seller
The above screen shot clearly shows -$55 deducted from my personal account
Below screen show Business account detail after get amount from buyer
The above screen shot clearly shows $55 amount get from user and total is increased
If you not redirect to your website after payment complete then follow the below steps to set return URL in business account.
a. Click on the business test account id and click enter Sandbox test site
b. Choose Profile --> More options in the menu under Selling Preferences choose Website Payment Preferences
c. Select Auto Return on radio button to redirect and enter return URL below like http://www.xyz.com if you don't have any domain just enter any valid domain name like your blog URL etc. because its only for testing
d. Enable on Payment Data Transfer to get payment data return in website and save it.
e. Again go to more option website payment reference and see identity token is generated (under payment data transfer) copy that identity token use it in the website web.config file. Source code:
Client Side: ASP.NET
Code Behind: C#Conclusion
I hope this article is help you to know about integrate PayPal in your website.
Hi Ravindran,
Thanks a lot for this article.
I followed your steps but after running the application and I clicked on 'Buy Now' button, it redirects me to the below link:
https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_xclick&business=vijay_1344262433_biz@gmail.com&first_name=vijay&city=mumbai&state=maharashtra&item_name=Laptop&amount=$100&shipping=5&handling=5&tax=5&quantity=1%c2%a4cy=USD&return=http://localhost:2525/PayPalApp/Success.aspx&cancel_return=http://localhost:2525/PayPalApp/Failed.aspx
Not to the page that you have shown in the article. May I know where I went wrong?