public ActionResult Create(VolumDiscount volumdiscount)
        {
            if (ModelState.IsValid)
            {
                volumdiscount.Id = Guid.NewGuid();
                db.VolumDiscounts.Add(volumdiscount);
                db.SaveChanges();
                return BreadCrum.RedirectToPreviousAction(Session, ControllerName);
            }

            ViewBag.ContractId = new SelectList(db.Contracts, "Id", "Name", volumdiscount.ContractId);
            return View(volumdiscount);
        }
 public ActionResult Edit(VolumDiscount volumdiscount)
 {
     if (ModelState.IsValid)
     {
         db.Entry(volumdiscount).State = EntityState.Modified;
         db.SaveChanges();
         return BreadCrum.RedirectToPreviousAction(Session, ControllerName);
     }
     ViewBag.ContractId = new SelectList(db.Contracts, "Id", "Name", volumdiscount.ContractId);
     return View(volumdiscount);
 }