如何使用MVC 5进行服务器端验证

I am working on a simple auction website for a charity. I have an Item model for the sale items, and a Bid view where the user can enter a bid and submit it. This bid is received inside the Item controller:

我正在一个简单的拍卖网站上为一家慈善机构工作。我有一个销售项目的项目模型，以及一个用户可以输入出价并提交出价的出价视图。此出价在项目控制器内收到：

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Bid(int itemID, int bidAmount)
    {
        if (ModelState.IsValid)
        {
            Item item = db.Items.Find(itemID);
            if (bidAmount >= item.NextBid)
            {
                item.Bids++;
                item.CurrentBid = bidAmount;
                item.HighBidder = HttpContext.User.Identity.Name;
                db.Entry(item).State = EntityState.Modified;
                db.SaveChanges();
            }
            else
            {
                // Already outbid
            }
            return View(item);
        }
        return RedirectToAction("Auction");
    }

I would like to know how to display server-side validation to the user. For example, in the above code, it may be that the submitted bid amount is no longer sufficient. In that case, I would like to display a message to the user that they have been outbid etc.

我想知道如何向用户显示服务器端验证。例如，在上面的代码中，提交的出价金额可能不再足够。在这种情况下，我想向用户显示一条消息，表明它们已被出价等。

How can I pass this information back to the view to display an appropriate message? I want the user to see the same item page view as before, updating the value in the edit box and displaying the message - similar to eBay. Thanks.

如何将此信息传递回视图以显示相应的消息？我希望用户看到与以前相同的项目页面视图，更新编辑框中的值并显示消息 - 类似于eBay。谢谢。

1 个解决方案

#1

you should have a look at the AddModelError Method of the ModelState Property.

您应该看一下ModelState属性的AddModelError方法。

   [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Bid(int itemID, int bidAmount)
    {
        if (ModelState.IsValid)
        {
            Item item = db.Items.Find(itemID);
            if (bidAmount >= item.NextBid)
            {
                item.Bids++;
                item.CurrentBid = bidAmount;
                item.HighBidder = HttpContext.User.Identity.Name;
                db.Entry(item).State = EntityState.Modified;
                db.SaveChanges();
            }
            else
            {
                // Already outbid
                ModelState.AddModelError("", "Already outbid");
            }
            return View(item);
        }
        return RedirectToAction("Auction");
    }

To Display the message in your view, you need a ValidationSummary

要在视图中显示消息，您需要ValidationSummary

@Html.ValidationSummary(true)

@ Html.ValidationSummary（真）

#1