ASP.NET MVC Html.TextBox 报 Object reference not set to an instance of an object 的解决方案

Control中代码如下：

 

 1
 2        [AcceptVerbs(HttpVerbs.Post)]
 3        public ActionResult Register(FormCollection collection)
 4        {
 5            string userName = collection["UserName"];
 6            if (string.IsNullOrEmpty(userName.Trim()))
 7            {
 8                ModelState.AddModelError("UserName", "用户名不能为空！");
 9                ModelState.SetModelValue("UserName", collection.ToValueProvider()["UserName"]);
10            }
11            else if (pwd != confirmPassword)
12            {
13                ModelState.AddModelError("ConfirmPassword", "密码不一致！");
14                ModelState.SetModelValue("ConfirmPassword", collection.ToValueProvider()["ConfirmPassword"]);
15            }
16            else
17            {
18                userInfoBusiness.AddUser(userInfo);
19                DoLogin(userName, pwd);
20                return RedirectToAction("Index", "Home");
21            }
22            return View(userInfo);
23        }

 

关键是要加： ModelState.SetModelValue("UserName", collection.ToValueProvider()["UserName"]);