public IActionResult Add()
        {
            PartHelperModel model = new PartHelperModel
            {
                Suppliers = this.supplierService.GetAll()
            };

            return(this.View(model));
        }
        public IActionResult Add(PartHelperModel model)
        {
            if (!this.ModelState.IsValid)
            {
                model.Suppliers = this.supplierService.GetAll();
                return(this.View(model));
            }

            this.partService.Add(model.Part.Name, model.Part.Price, model.Part.SupplierId, model.Part.Quantity);
            return(this.RedirectToAction(nameof(Index)));
        }