public ActionResult Edit(TermsOfPayment termsofpayment)
 {
     if (ModelState.IsValid)
     {
         db.Entry(termsofpayment).State = EntityState.Modified;
         db.SaveChanges();
         return RedirectToAction("Index");
     }
     return View(termsofpayment);
 }
        public ActionResult Create(TermsOfPayment termsofpayment)
        {
            ModelState.Remove("topNo");
            if (ModelState.IsValid)
            {
                // generate new TermsOfPayment id
                var lastId = db.TermsOfPayments.Max(items => items.topNo);
                var newId = lastId + 1;
                termsofpayment.topNo = newId; 
                db.TermsOfPayments.Add(termsofpayment);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(termsofpayment);
        }