从 POST 操作验证模态后无法正常工作

Question

我在我的应用程序中使用模态局部视图。我正在验证我的模型是否有错误我正在使用 ModelState.AddModelError() 返回模型，但它不能正常工作。另外，我无法加载 SelectLists。

public ActionResult StockOut(StockOut model)
    {
        if (ModelState.IsValid)
        {
            var stock = (from s in db.Stocks where s.ProductId == model.ProductId select s).FirstOrDefault();
            if (stock.Quantity > 0 && model.Quantity <= stock.Quantity)
            {
                var weight = ((from p in db.Products where p.Id == model.ProductId select p).FirstOrDefault().NetWeight) * model.Quantity;
                stock.Quantity -= model.Quantity;
                stock.TotalWeight -= weight;
                StockOut entity = new StockOut()
                {
                    DriverId = model.DriverId,
                    LastUpdated = DateTime.Now,
                    ProductId = model.ProductId,
                    Quantity = model.Quantity,
                    TotalWeight = weight
                };
                db.StockOut.Add(entity);
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            else
            {
                ModelState.AddModelError("Quantity", "Please Enter A Valid Quantity");
                ViewBag.ProductId = new SelectList(db.Products.ToList(), model.ProductId);
                ViewBag.DriverId = new SelectList(db.Products.ToList(), model.DriverId);
            }
        }
        ViewBag.ProductId = new SelectList(db.Products.ToList(), model.ProductId);
        ViewBag.DriverId = new SelectList(db.Users.ToList(), model.DriverId);
        return PartialView(model);
    }

提交前：

出现错误后

Answer 1

修复你选择列表，你创建它们两次，删除一组（在 if 中）

ViewBag.ProductId = new SelectList(db.Products.ToList(),"Id", "Name" , model.ProductId);

///Are you sure that you have have to use products again?

ViewBag.DriverId = new SelectList(db.Products.ToList(),"Id", 
"Name" , model.DriverId);

如果你想使用 AddModelError 你必须添加到表单

@Html.ValidationSummary(false)