错误 1 ​​找不到类型或命名空间名称“控制器”（是否缺少 using 指令或程序集引用？）

当我尝试在 asp.net mvc3 中构建项目时。出现27个错误，说mvc相关的类不存在：

下面是一个例子：

Error   1   The type or namespace name 'Controller' could not be found (are you missing a using directive or an assembly reference?)    C:\Documents and Settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication1\MvcApplication1\Controllers\HomeController.cs   10  35  MvcApplication1

UPDATE

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

namespace MvcApplication2.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            ViewBag.Message = "Welcome to ASP.NET MVC!";

            return View();
        }

        public ActionResult About()
        {
            return View();
        }
    }
}

Errors:

Error   1   The type or namespace name 'Controller' could not be found (are you missing a using directive or an assembly reference?)    c:\documents and settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication2\MvcApplication2\Controllers\HomeController.cs   9   35  MvcApplication2

Error   2   The type or namespace name 'ActionResult' could not be found (are you missing a using directive or an assembly reference?)  c:\documents and settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication2\MvcApplication2\Controllers\HomeController.cs   11  16  MvcApplication2


Error   3   The name 'ViewBag' does not exist in the current context    c:\documents and settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication2\MvcApplication2\Controllers\HomeController.cs   13  13  MvcApplication2


Error   4   The name 'View' does not exist in the current context   c:\documents and settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication2\MvcApplication2\Controllers\HomeController.cs   15  20  MvcApplication2


Error   5   The type or namespace name 'ActionResult' could not be found (are you missing a using directive or an assembly reference?)  c:\documents and settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication2\MvcApplication2\Controllers\HomeController.cs   18  16  MvcApplication2


Error   6   The name 'View' does not exist in the current context   c:\documents and settings\hhhhhhhh\my documents\visual studio 2010\Projects\MvcApplication2\MvcApplication2\Controllers\HomeController.cs   20  20  MvcApplication2

您需要添加System.Web.Mvc到您的项目参考。

1. 右键单击参考文献
2. Click “添加参考...”
3. 组件 > 框架
4. Search Assemblies (Ctrl+E) for System.Web.Mvc (you will probably have more: version 2/3/4)