public ActionResult SetSupply(SetSupplyViewModel viewModel)
        {
            var result = supplySlots.Update(viewModel.SupplySlotId, viewModel.SupplyId);

            if (result.Success)
            {
                return(RedirectToAction("Supplies", new { id = viewModel.PrinterId }));
            }
            else
            {
                AddModelStateErrors(result);
            }

            viewModel.CompatibleSupplies = SuppliesToSelectList(supplies.GetCompatibleNotInUse(viewModel.PrinterModelId));

            return(View(viewModel));
        }
        // GET: Printers/SetSupply/5
        public ActionResult SetSupply(int?id)
        {
            if (id == null)
            {
                return(new HttpStatusCodeResult(HttpStatusCode.BadRequest));
            }

            var supplySlot = supplySlots.GetById((int)id);

            if (supplySlot == null)
            {
                return(HttpNotFound());
            }

            var viewModel = new SetSupplyViewModel(supplySlot);

            viewModel.CompatibleSupplies = SuppliesToSelectList(supplies.GetCompatibleNotInUse(viewModel.PrinterModelId));

            return(View(viewModel));
        }