Question

有没有办法在外部程序集中通过builder.RegisterControllers()加载的控制器中启用注入？当我在我的插件文件夹中复制完全相同的程序集时，我得到一个无参数构造函数未找到错误。

// This doesnt work, parameterless constructor not found!
var assemblies = new DirectoryInfo(
                      HttpContext.Current.Server.MapPath("~/App_Plugins/"))
                .GetFiles("*.dll")
                .Select(r => Assembly.LoadFrom(r.FullName)).ToArray();  

// This works, injection happens correctly on constructor
var assemblies = new[] {typeof (MvcApplication).Assembly};

第二个将起作用，而第一个将产生错误。我已经尝试过manualy也注册了“外部”控制器，但仍然存在同样的问题：

builder.RegisterAssemblyTypes(assemblies)
      .Where(r => r.BaseType == typeof(Controller))
      .InstancePerHttpRequest();

我正在使用mvc 4的DefaultControllerFactory

堆栈跟踪是这样的：

No parameterless constructor defined for this object.

[MissingMethodException: No parameterless constructor defined for this object.]
   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, StackCrawlMark& stackMark) +113
   System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +232
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +83
   System.Activator.CreateInstance(Type type) +6
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +55

[InvalidOperationException: An error occurred when trying to create a controller of type 'TestProject.Controllers.HomeController'. Make sure that the controller has a parameterless public constructor.]
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +178
   System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +77
   System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +66
   System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +191
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +50
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +48
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +16
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +301
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

我没有看到Autofac参与堆栈跟踪。如果Autofac不满意，那么异常就像是：

[DependencyResolutionException: None of the constructors found with 'Public binding flags' on type 'SomeApp.WebApplication.Areas.Shared.Controllers.AccountController' can be invoked with the available services and parameters:
Cannot resolve parameter 'SomeApp.WebApplication.Areas.Shared.Controllers.Slappy slappy' of constructor 'Void .ctor(SomeApp.Web.LoginService, SomeApp.Web.AccountMembership.IMembershipService, SomeApp.Infrastructure.Logging.ILog, SomeApp.WebApplication.Areas.Shared.Controllers.Slappy)'.]
   Autofac.Core.Activators.Reflection.ReflectionActivator.ActivateInstance(IComponentContext context, IEnumerable`1 parameters) +377
   Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable`1 parameters) +48
   Autofac.Core.Resolving.InstanceLookup.Execute() +48
   Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable`1 parameters) +167
   Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable`1 parameters) +64
   Autofac.Core.Lifetime.LifetimeScope.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters) +163
   Autofac.ResolutionExtensions.TryResolveService(IComponentContext context, Service service, IEnumerable`1 parameters, Object& instance) +70
   Autofac.ResolutionExtensions.ResolveOptionalService(IComponentContext context, Service service, IEnumerable`1 parameters) +53
   Autofac.Integration.Mvc.AutofacDependencyResolver.GetService(Type serviceType) +59
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +41

[InvalidOperationException: An error occurred when trying to create a controller of type 'SomeApp.WebApplication.Areas.Shared.Controllers.AccountController'. Make sure that the controller has a parameterless public constructor.]
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +179
   System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +80
   System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +74
   System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +196
   System.Web.Mvc.<>c__DisplayClass6.<BeginProcessRequest>b__2() +49
   System.Web.Mvc.<>c__DisplayClassb`1.<ProcessInApplicationTrust>b__a() +13
   System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f) +7
   System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) +22
   System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Func`1 func) +88
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +98
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +50
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +16
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +301
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

确认您正在设置DependencyResolver。

DependencyResolver.SetResolver(new AutofacDependencyResolver(ApplicationContainer));

Autofac注入到加载了RegisterControllers（）的控制器

1 个答案: