How to integrate BillDesk Payment Gateway with Asp.Net Website

1. Add all dll from the Library folder which is sent by CCAvenue to your Gac
2. From Avenue Integration kit you will get three pages - Data.aspx, SubmitData.aspx and ResponseHandler.aspx
3. On your button you have to pass your OrderID, MerchantID (given by CCAvenue), Amount and Redirect URL (your website url so ASA Payment will complete user redirect to your site) to Data.aspx page.
4. Initialize your TextBox of Data.aspx as per the value which you will get after click of checkout button as i shown above in 3rd picture.
5. In SubmitData.aspx.cs page, initialize your working key on workingkey variable ( you will get your working key after login into your CCAvenue account).

After following this step you can integrate Avenue gateway to your button

For details refer this -

http://bhartiwebworld.blogspot.in/2013/09/how-to-do-ccavenue-payment-gateway.html

You can also integrate using magento. For magento check this video -

https://www.youtube.com/watch?v=4e1SiQM-sHA