Asp.net MVC 的 Model验证

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
namespace mytest2.Models
{
public class guests
{
[Key]
[Required(ErrorMessage="请输入名字")]
public string name { get; set; }
[Required(ErrorMessage = "请输入电话号码")]
public string phone { get; set; }
}
}

[HttpPost]
public ActionResult Guest(guests guests)
{
if(ModelState.IsValid)
{
return Content("success");
}
else
{
if(string.IsNullOrEmpty(guests.name))
{
ModelState.AddModelError("name","姓名不能为空");
}

}
return View();
}

<form   method="post">
<span>第一个 </span>
@Html.ValidationSummary(true)
<span></span><input id="name" name="name" />
<p>@Html.ValidationMessageFor(m => m.name)</p>
<span></span><input id="phone" name="phone" />
<p>@Html.ValidationMessageFor(m => m.phone)</p>
<button type="submit" >anniu</button>
</form>