带有Postal和Unity的依赖注入异常

Question

在我的ASP.NET Web控制器(v5.1)中，我希望切换到使用IEMailService on 邮政 (v0.9.1)，因此我在控制器上做了如下操作：

public class HomeController : Controller
{
  private readonly IEmailService _emailService;

  public HomeController(IEmailService emailService)
  {
    if (emailService == null)
      throw new ArgumentNullException("emailService");
    _emailService = emailService;
  }
}

My (v3.0)容器设置：

container.RegisterType<IEmailService, EmailService>();
container.RegisterType<IEmailViewRenderer, EmailViewRenderer>();
container.RegisterType<IEmailParser, EmailParser>();

但我得到了这个例外，我无法理解。

团结到底想告诉我什么？

The type IList`1 does not have an accessible constructor.

堆栈跟踪：

[InvalidOperationException: The type IList`1 does not have an accessible constructor.]
   Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.ThrowForNullExistingObject(IBuilderContext context) +239
   lambda_method(Closure , IBuilderContext ) +60
   Microsoft.Practices.ObjectBuilder2.<>c__DisplayClass1.<GetBuildMethod>b__0(IBuilderContext context) +71
   Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) +42
   Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) +333
   Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) +274
   Microsoft.Practices.ObjectBuilder2.BuilderContext.NewBuildUp(NamedTypeBuildKey newBuildKey) +250
   Microsoft.Practices.Unity.ObjectBuilder.NamedTypeDependencyResolverPolicy.Resolve(IBuilderContext context) +101
   lambda_method(Closure , IBuilderContext ) +205
   Microsoft.Practices.ObjectBuilder2.<>c__DisplayClass1.<GetBuildMethod>b__0(IBuilderContext context) +71
   Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) +42
   Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) +333
   Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) +274
   Microsoft.Practices.ObjectBuilder2.BuilderContext.NewBuildUp(NamedTypeBuildKey newBuildKey) +250
   Microsoft.Practices.Unity.ObjectBuilder.NamedTypeDependencyResolverPolicy.Resolve(IBuilderContext context) +101
   lambda_method(Closure , IBuilderContext ) +205
   Microsoft.Practices.ObjectBuilder2.<>c__DisplayClass1.<GetBuildMethod>b__0(IBuilderContext context) +71
   Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) +42
   Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) +333
   Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) +274
   Microsoft.Practices.ObjectBuilder2.BuilderContext.NewBuildUp(NamedTypeBuildKey newBuildKey) +250
   Microsoft.Practices.Unity.ObjectBuilder.NamedTypeDependencyResolverPolicy.Resolve(IBuilderContext context) +101
   lambda_method(Closure , IBuilderContext ) +231
   Microsoft.Practices.ObjectBuilder2.<>c__DisplayClass1.<GetBuildMethod>b__0(IBuilderContext context) +71
   Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) +42
   Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) +333
   Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) +274
   Microsoft.Practices.ObjectBuilder2.BuilderContext.NewBuildUp(NamedTypeBuildKey newBuildKey) +250
   Microsoft.Practices.Unity.ObjectBuilder.NamedTypeDependencyResolverPolicy.Resolve(IBuilderContext context) +101
   lambda_method(Closure , IBuilderContext ) +209
   Microsoft.Practices.ObjectBuilder2.<>c__DisplayClass1.<GetBuildMethod>b__0(IBuilderContext context) +71
   Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) +42
   Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) +333
   Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) +274
   Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name, IEnumerable`1 resolverOverrides) +383

[ResolutionFailedException: Resolution of the dependency failed, type = "PostalTest.Controllers.HomeController", name = "(none)".
Exception occurred while: while resolving.
Exception is: InvalidOperationException - The type IList`1 does not have an accessible constructor.
-----------------------------------------------
At the time of the exception, the container was:

  Resolving PostalTest.Controllers.HomeController,(none)
  Resolving parameter "emailService" of constructor PostalTest.Controllers.HomeController(Postal.IEmailService emailService)
    Resolving Postal.EmailService,(none) (mapped from Postal.IEmailService, (none))
    Resolving parameter "emailViewRenderer" of constructor Postal.EmailService(Postal.IEmailViewRenderer emailViewRenderer, Postal.IEmailParser emailParser, System.Func`1[[System.Net.Mail.SmtpClient, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] createSmtpClient)
      Resolving Postal.EmailViewRenderer,(none) (mapped from Postal.IEmailViewRenderer, (none))
      Resolving parameter "viewEngines" of constructor Postal.EmailViewRenderer(System.Web.Mvc.ViewEngineCollection viewEngines)
        Resolving System.Web.Mvc.ViewEngineCollection,(none)
        Resolving parameter "list" of constructor System.Web.Mvc.ViewEngineCollection(System.Collections.Generic.IList`1[[System.Web.Mvc.IViewEngine, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] list)
          Resolving System.Collections.Generic.IList`1[System.Web.Mvc.IViewEngine],(none)
]
   Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name, IEnumerable`1 resolverOverrides) +446
   Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, String name, IEnumerable`1 resolverOverrides) +50
   Microsoft.Practices.Unity.UnityContainer.Resolve(Type t, String name, ResolverOverride[] resolverOverrides) +48
   Microsoft.Practices.Unity.UnityContainerExtensions.Resolve(IUnityContainer container, Type t, ResolverOverride[] overrides) +61
   Unity.Mvc5.UnityDependencyResolver.GetService(Type serviceType) +140
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +87

[InvalidOperationException: An error occurred when trying to create a controller of type 'PostalTest.Controllers.HomeController'. Make sure that the controller has a parameterless public constructor.]
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +247
   System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +438
   System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +226
   System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +326
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +157
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +88
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +50
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +301
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

我不使用团结，但你能注册一个电子邮件服务的实例吗？

container.RegisterInstance<IEmailService>(new EmailService());