public ActionResult New(NewCartonForm form)
        {
            if (!ModelState.IsValid)
            {
                return RedirectToAction<CartonController>(c => c.New())
                .WithError("Invalid Input!");
            }

            _context.Cartons.Add(new Carton
            {
                ItemId = form.ItemId,
                NumberOfPieces = form.NumberOfPieces

            });

            _context.SaveChanges();

            return RedirectToAction<CartonController>(c => c.Index())
                .WithSuccess("Carton created!");
        }
        public ActionResult New()
        {
            var alreadySetupInCartonItems = _context.Cartons.Select(c => c.ItemId).ToArray();

            var form = new NewCartonForm
            {
                //ItemList =
                //    _context.Items.ToListItems(t => (t.ItemCode + " - " + t.ItemName),
                //        v => v.ItemId.ToString(CultureInfo.InvariantCulture), "Please Select...")



                ItemList =
                    _context.Items.Where(i => !alreadySetupInCartonItems.Contains(i.ItemId)).ToListItems(t => (t.ItemCode + " - " + t.ItemName),
                        v => v.ItemId.ToString(CultureInfo.InvariantCulture), "Please Select...")
            };


            return View(form);
        }