在MVC 中使用 autofac 实现自动注册

思路很简单：首先我们去找到所有Dll，再去找到实现了IAutoInject 接口的类，然后使用RegisterAssemblyTypes进行注入。IAutoInject是一个空接口，用来辅助我们寻找需要注册的接口

1. 在控制台执行命令安装AutoFac组件

Install-Package Autofac

Install-Package Autofac.Mvc5 -Version 4.0.2

2. 定义IAutoInject接口

public interface IAutoInject { }

3. 在Application_Start()中初始化

protected void Application_Start()
{
var builder = new ContainerBuilder();
//获取IAutoInject的Type
var baseType = typeof(IAutoInject);
//获取所有程序集
var assemblies = System.Web.Compilation.BuildManager.GetReferencedAssemblies().Cast<Assembly>().ToArray();
//自动注册接口
builder.RegisterAssemblyTypes(assemblies).Where(b => b.GetInterfaces().
Any(c => c == baseType && b != baseType)).AsImplementedInterfaces(). InstancePerLifetimeScope();
//自动注册控制器
builder.RegisterControllers(assemblies);
var container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
}

注意： 获取程序集的错误写法(该写法在回收程序池后会导致注册信息丢失)： var assemblies = AppDomain.CurrentDomain.GetAssemblies().ToArray();

4. 编写测试代码

public interface IStudent: IAutoInject
{
string Test();
}

public class Student : IStudent
{
public string Test()
{
return "ok";
}
}

public class HomeController : Controller
{
private IStudent _student;

public HomeController(IStudent student)
{
_student = student;
}

public ActionResult Index()
{
return Content(_student.Test());
}
}

访问Home/index 即可看到ok成功输出

autofac官网: https://autofac.org/