using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace Server_Side_Validation_IN_MVC.Models
{
 public class Customer
 {
  public string Name { get; set; }
  public string Email { get; set; }
 }
}

using FluentValidation;
using Server_Side_Validation_IN_MVC.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace Server_Side_Validation_IN_MVC.Validator
{
 public class CustomerValidator:AbstractValidator<Customer>
 {
  public CustomerValidator()
  {
   RuleFor(s => s.Name).NotEmpty().WithMessage("名字不能为空");
   RuleFor(s => s.Email).NotEmpty().WithMessage("电子邮件不能为空");
   RuleFor(s => s.Email).EmailAddress().WithMessage("电子邮件格式不合法");
  }
 }
}

using FluentValidation.Results;
using Server_Side_Validation_IN_MVC.Models;
using Server_Side_Validation_IN_MVC.Validator;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace Server_Side_Validation_IN_MVC.Controllers
{
 public class CustomerController : Controller
 {
  // GET: Customer
  public ActionResult Index()
  {
   return View();
  }

  [HttpPost]
  public ActionResult Index(Customer model)
  {
   CustomerValidator validator = new CustomerValidator();
   ValidationResult result = validator.Validate(model);

   if (result.IsValid)
   {
    ViewBag.Name = model.Name;
    ViewBag.Email = model.Email;
   }
   else
   {
    foreach (var item in result.Errors)
    {
     ModelState.AddModelError(item.PropertyName, item.ErrorMessage);
    }
   }
   return View(model);
  }
 }
}

public static void RegisterRoutes(RouteCollection routes)
  {
   routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

   routes.MapRoute(
    name: "Default",
    url: "{controller}/{action}/{id}",
    defaults: new { controller = "Customer", action = "Index", id = UrlParameter.Optional }
   );
  }