解决Autofac MVC 自动注入在 Areas拆分到不同dll下的注入失败问题

由于项目业务复杂，创建了多个Areas 并把他们放在了不同的项目中，项目使用AutoFac做的IOC

配置代码为

 1  public class MvcApplication : System.Web.HttpApplication

 2     {

 3         protected void Application_Start()

 4         {

 5             //依赖注入

 6             var builder = new ContainerBuilder();

 7             builder.RegisterModule(new ConfigurationSettingsReader("autofac"));

 8             builder.RegisterControllers(Assembly.GetExecutingAssembly());

 9 

10             var container = builder.Build();

11             DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

12 

13             AreaRegistration.RegisterAllAreas();

14                 WebApiConfig.Register(GlobalConfiguration.Configuration);

15             FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

16             RouteConfig.RegisterRoutes(RouteTable.Routes);

17         }

18     }

在 Controllers中 采用 构造函数来实现注入

namespace xxx.Web.Person.Controllers

{

    /// <summary>

    /// 定位模块

    /// </summary>

    public class LocationController : Controller

    {

        private ILocationService _location;

        public LocationController(ILocationService location)

        {

            _location = location;

        }

    }

}

启动后报错 错误信息：

[MissingMethodException: 没有为该对象定义无参数的构造函数。]

   System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0

   System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache) +98

   System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean skipCheckThis, Boolean fillCache) +241

   System.Activator.CreateInstance(Type type, Boolean nonPublic) +69

   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +67

[InvalidOperationException: 尝试创建“xxx.Web.Person.Controllers.HomeController”类型的控制器时出错。请确保控制器具有无参数公共构造函数。]

通过错误信息得知 AutoFac 的RegisterControllers 只是 注入了xxx.Web的 Controllers 对于引用的 xxx.web.Person.dll 下的 Controller 没有注入。
解决方法如下：

 public class MvcApplication : System.Web.HttpApplication

    {

        protected void Application_Start()

        {

            //依赖注入

            var builder = new ContainerBuilder();

            builder.RegisterModule(new ConfigurationSettingsReader("autofac"));

            builder.RegisterControllers(Assembly.GetExecutingAssembly());



            //解决Areas在不同的Dll中注入问题

            var assemblies = new DirectoryInfo(

                      HttpContext.Current.Server.MapPath("~/bin/"))

                .GetFiles("*.dll")

                .Select(r => Assembly.LoadFrom(r.FullName)).ToArray();

            builder.RegisterAssemblyTypes(assemblies)

                .Where(r => r.BaseType == typeof(Controller))

                .InstancePerHttpRequest();



            var container = builder.Build();

            DependencyResolver.SetResolver(new AutofacDependencyResolver(container));





            AreaRegistration.RegisterAllAreas();

            WebApiConfig.Register(GlobalConfiguration.Configuration);

            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

            RouteConfig.RegisterRoutes(RouteTable.Routes);

        }

    }

　　重新编译  运行正常。