public ActionResult Edit(ProductViewModel model) { if (ModelState.IsValid) { Product p = new Product() { ProductID = model.ProductID, ProductName = model.ProductName, CategoryID = model.CategoryID, SupplierID = model.SupplierID, Quantity = (Int32)model.Quantity, UnitPrice = model.UnitPrice, Description = model.Description }; pbo.EditProduct(p); return(RedirectToAction("Index")); } ModelState.AddModelError("", "Error input!"); ViewBag.Cat = new SelectList(catbo.GetAllCat(), "CategoryID", "CategoryName"); return(View(model)); }