Autofac 同时支持MVC 与Webapi

　　　　　　// Get your HttpConfiguration.
            var config = GlobalConfiguration.Configuration;

            var builder = new ContainerBuilder();
            //builder.RegisterType<Helper>().As<IHelper>().InstancePerLifetimeScope();

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

            // OPTIONAL: Register the Autofac filter provider.
            builder.RegisterWebApiFilterProvider(config);
            var container = builder.Build();
            config.DependencyResolver = new AutofacWebApiDependencyResolver(container);

            DependencyResolver.SetResolver(new AutofacDependencyResolver(container));