public ActionResult Index(PromotionModelView model)
 {
     try
     {
         List <Promotion> list = db.Promotions.ToList();
         if (model.Id > 0)
         {
             //update
             Promotion promotion = db.Promotions.SingleOrDefault(x => x.PromotionId == model.Id);
             promotion.PromotionId = model.Id;
             promotion.Name        = model.Name;
             promotion.SaleOff     = model.SaleOff;
             db.SaveChanges();
         }
         else
         {
             //Insert
             Promotion promotion = new Promotion
             {
                 Name    = model.Name,
                 SaleOff = model.SaleOff
             };
             db.Promotions.Add(promotion);
             db.SaveChanges();
         }
         return(View(model));
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }
        public ActionResult AddEditPromotion(int Id)
        {
            List <Promotion>   listPromotion = db.Promotions.ToList();
            PromotionModelView model         = new PromotionModelView();

            if (Id > 0)
            {
                Promotion promotion = db.Promotions.SingleOrDefault(x => x.PromotionId == Id);
                model.Id      = promotion.PromotionId;
                model.Name    = promotion.Name;
                model.SaleOff = promotion.SaleOff;
            }
            return(PartialView("Details", model));
        }