Autofac+Mvc4依赖注入

        前段时间也研究了其他IOC框架，如unity、Castle、Autofac,相对来说Autofac比较简单，据说也是效率最高的。首先了解下控制反转和依赖注入 IoC把创建依赖对象的控制权交给了容器，由容器进行注入对象，所以对象与对象之间是松散耦合，利于功能复用，也使得程序的整个体系结构变得非常灵活。

　控制反转Ioc：调用者不主动创建被调用者实例，由IoC容器来创建;

   依赖注入DI：把依赖关系注入到调用者；

Autofac+Mvc4 项目架构

Student.cs实体

    public class Student
    {
        public string name { get; set; }
        public int age { get; set; }
        public string gender { get; set; }
    }

IStudentRepository.cs接口

    public interface IStudentRepository
    {
        IEnumerable<Student> GetAll();
    }

StudentRepository实现接口

 public class StudentRepository : IStudentRepository
    {
        private List<Student> Articles = new List<Student>(){
            new Student { name = "张三", gender = "male", age = 12 },
            new Student { name = "李四", gender = "fmale", age = 15 },
            new Student { name = "王五", gender = "fmale", age = 13 }};

        /// <summary>
        /// 获取全部学生信息
        /// </summary>
        /// <returns></returns>
        public IEnumerable<Student> GetAll()
        {
            return Articles;
        }
    }

HomeControll.cs控制器

        #region [AutoFac注入]

        readonly IStudentRepository repository;
        //构造器注入
        public HomeController(IStudentRepository repository)
        {
            this.repository = repository;
        }

        /// <summary>
        /// AutoFac注入
        /// </summary>
        /// <returns></returns>
        public ActionResult StudentIndex()
        {
            var data = repository.GetAll();
            return View(data);
        }
        #endregion

在App_Start文件夹中添加AutofacConfig.cs文件

public class AutofacConfig
    {
        /// <summary>
        /// 负责调用autofac框架实现业务逻辑层和数据仓储层程序集中的类型对象的创建
        /// 负责创建MVC控制器类的对象(调用控制器中的有参构造函数)
        /// </summary>
        public static void Register()
        {
            ContainerBuilder builder = new ContainerBuilder();
            SetupResolveRules(builder); 
            builder.RegisterControllers(Assembly.GetExecutingAssembly());
            builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()).AsImplementedInterfaces();
            var container = builder.Build();
            DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

        }
        /// <summary>
        /// 所有需要注入的类型
        /// </summary>
        /// <param name="builder"></param>
        private static void SetupResolveRules(ContainerBuilder builder)
        {
            builder.RegisterType<StudentRepository>().As<IStudentRepository>();
        }
    }

在Global.asax.cs类Application_Start方法中注册Autofac 

 public class MvcApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            WebApiConfig.Register(GlobalConfiguration.Configuration);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
            
            AutofacConfig.Register();//AutoFac注入
        }
    }

执行程序返回数据

可以参考http://www.cnblogs.com/bubugao/p/AutofacDemo.html文章，简单明了解释Autofac作用。