// So called "Result Url" in terms of Robokassa documentation.
        // This url is called by Robokassa robot.
        public ActionResult Confirm(RobokassaConfirmationRequest confirmationRequest)
        {
            try
            {
                if (confirmationRequest.IsQueryValid(RobokassaQueryType.ResultURL))
                {
                    processOrder(confirmationRequest);

                    return Content("OK"); // content for robot
                }
            }
            catch (Exception) { }
            return Content("ERR");
        }
        // So called "Success Url" in terms of Robokassa documentation.
        // Customer is redirected to this url after successful payment.
        public ActionResult Success(RobokassaConfirmationRequest confirmationRequest)
        {
            try
            {

                if (confirmationRequest.IsQueryValid(RobokassaQueryType.SuccessURL))
                {
                    processOrder(confirmationRequest);

                    return View(); // content for user
                }
            }
            catch (Exception) { }

            return View("Fail");
        }
 private void processOrder(RobokassaConfirmationRequest confirmationRequest)
 {
     // TODO:
     // 1. verify your order Id and price here
     // 2. mark your order as paid
 }