Question

以下是global.asax

中的Bootstrap

public class Global : HttpApplication {
        void Application_Start(object sender, EventArgs e) {
            AreaRegistration.RegisterAllAreas();
            GlobalConfiguration.Configure(WebApiConfig.Register);
            RouteConfig.RegisterRoutes(RouteTable.Routes);

            // initiate dependency injection resolver
            DependencyInjectionResolver.RegisterDependencies(typeof(Global).Assembly);
        }
    }

以下是实施

public class DependencyInjectionResolver {
    private static IContainer _container;

    public static TService Resolve<TService>() {
        return DependencyResolver.Current.GetService<TService>();
    }

    public static void RegisterDependencies(Assembly assembly) {
        var builder = new ContainerBuilder();
        builder.RegisterFilterProvider();
        builder.RegisterControllers(Assembly.GetExecutingAssembly());
        builder.RegisterApiControllers(Assembly.GetExecutingAssembly());

        builder.RegisterGeneric(typeof (Repository<>))
            .As(typeof (IRepository<>))
            .InstancePerHttpRequest()
            .InstancePerLifetimeScope();

        builder.RegisterType<LoggerService>()
            .As<ILoggerService>()
            .InstancePerApiRequest()
            .InstancePerHttpRequest();

        builder.Register(x =>
            new MessageDataService(Resolve<ILoggerService>(), Resolve<IRepository<ApiRequestHistory>>()))
            .As<IMessagesDataService>()
            .InstancePerHttpRequest()
            .InstancePerApiRequest();

        #region setup

        _container = builder.Build();
        DependencyResolver.SetResolver(new AutofacDependencyResolver(_container));
        GlobalConfiguration.Configuration.DependencyResolver 
            = new AutofacWebApiDependencyResolver(_container);
        #endregion
    }
}

以下是我的例外：

    An error has occurred.An error occurred when trying to create a controller of type 'MessageReportController'. Make sure that the controller has a parameterless public constructor.System.InvalidOperationException   at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
   at System.Web.Http.Controllers.HttpControllerDescriptor.CreateController(HttpRequestMessage request)
   at System.Web.Http.Dispatcher.HttpControllerDispatcher.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__0.MoveNext()An error has occurred.Type 'WayToLead.Web.UI.api.MessageReportController' does not have a default constructorSystem.ArgumentException   at System.Linq.Expressions.Expression.New(Type type)
   at System.Web.Http.Internal.TypeActivator.Create[TBase](Type instanceType)
   at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.GetInstanceOrActivator(HttpRequestMessage request, Type controllerType, Func`1& activator)
   at System.Web.Http.Dispatcher.DefaultHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)

如何修复它以使用WebApi和Mvc控制器？

Answer 1

检查您是否已注册所有ApiControllers的依赖项和子依赖项。在堆栈跟踪深处的某处，您可能会发现AutoFac无法解析的依赖关系。

我猜测，由于AutoFac无法满足所有依赖关系，因此默认依赖项解析器将接管。

Autofac MVC5和WebAPI2.1无法正常工作

1 个答案: