Go to Paypal Checkout Cnntroller Action

public ActionResult Gotopaypal()
        {
            int id = (int)Session["checkoutcourseid"];
            var c = db.Courses.Find(id);


            return Redirect("https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_xclick&business=ahsanchaudary10@gmail.com&currency=USD&amount=" + Convert.ToDouble(c.course_price.ToString()) + "&item_name=Tutoronic&return=https://localhost:44367/Checkout/OrderBook");

        }