Ninject请求范围已经被释放。

Question

我在MVC 3应用程序中使用Ninject和扩展EventBroker和DependencyCreation。我已经安装并正在使用Ninject.MVC3包，因此也使用了OnePerRequestModule。

我正在尝试将名为IParentService的服务注入到控制器中。IParentService依赖于通过DependencyCreation扩展创建的ChildService (没有硬引用)。

这两个服务都在本地事件代理实例(本地到ParentService)上注册。

我希望每个请求都限定IParentService的作用域，并且希望在处理IParentService的同时处理依赖项和事件代理，但是，我得到了一个ScopeDisposedException。我做错什么了？

一些代码：

服务定义：

public interface IParentService
{
}

public class ParentService : IParentService
{
    [EventPublication("topic://ParentService/MyEvent")]
    public event EventHandler<EventArgs> MyEvent;
}

public class ChildService
{
    [EventSubscription("topic://ParentService/MyEvent", typeof(bbv.Common.EventBroker.Handlers.Publisher))]
    public void OnMyEvent(object sender, EventArgs eventArgs)
    {            
    }
}

内核注册(NinjectWebCommon)

    private static void RegisterServices(IKernel kernel)
    {
        kernel.Bind<IParentService>().To<ParentService>()
            .InRequestScope()
            .OwnsEventBroker("ParentServiceBroker")
            .RegisterOnEventBroker("ParentServiceBroker");

        kernel.DefineDependency<IParentService, ChildService>();
        kernel.Bind<ChildService>().ToSelf()
            .WhenInjectedInto<ParentService>()
            .InDependencyCreatorScope()
            .RegisterOnEventBroker("ParentServiceBroker");            
    }  

堆栈跟踪：

[ScopeDisposedException: The requested scope has already been disposed.]
   Ninject.Extensions.NamedScope.NamedScopeExtensionMethods.GetScope(IContext context, String scopeParameterName) in c:\Projects\Ninject\ninject.extensions.namedscope\src\Ninject.Extensions.NamedScope\NamedScopeExtensionMethods.cs:118
   Ninject.Extensions.NamedScope.NamedScopeExtensionMethods.GetScope(IContext context, String scopeParameterName) in c:\Projects\Ninject\ninject.extensions.namedscope\src\Ninject.Extensions.NamedScope\NamedScopeExtensionMethods.cs:126
   Ninject.Extensions.NamedScope.<>c__DisplayClass1`1.<InNamedScope>b__0(IContext context) in c:\Projects\Ninject\ninject.extensions.namedscope\src\Ninject.Extensions.NamedScope\NamedScopeExtensionMethods.cs:40
   Ninject.Planning.Bindings.BindingConfiguration.GetScope(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Bindings\BindingConfiguration.cs:119
   Ninject.Planning.Bindings.Binding.GetScope(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Bindings\Binding.cs:224
   Ninject.Activation.Context.GetScope() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:123
   Ninject.Activation.Caching.Cache.TryGet(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Caching\Cache.cs:110
   Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:150
   Ninject.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:386
   System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145
   System.Linq.<CastIterator>d__b1`1.MoveNext() +85
   System.Linq.Enumerable.Single(IEnumerable`1 source) +191
   Ninject.ResolutionExtensions.Get(IResolutionRoot root, String name, IParameter[] parameters) in c:\Projects\Ninject\ninject\src\Ninject\Syntax\ResolutionExtensions.cs:50
   Ninject.Extensions.ContextPreservation.ContextPreservationExtensionMethods.ContextPreservingGet(IContext context, String name, IParameter[] parameters) in c:\Projects\Ninject\ninject.extensions.contextpreservation\src\Ninject.Extensions.ContextPreservation\ContextPreservationExtensionMethods.cs:56
   Ninject.Extensions.bbvEventBroker.<>c__DisplayClass2`1.<RegisterOnEventBroker>b__0(IContext ctx, T instance) in c:\Projects\Ninject\ninject.extensions.bbveventbroker\src\Ninject.Extensions.bbvEventBroker\EventBrokerExtensionMethods.cs:45
   Ninject.Planning.Bindings.<>c__DisplayClass29`1.<OnDeactivation>b__28(IContext context, Object instance) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Bindings\BindingConfigurationBuilder.cs:513
   Ninject.Activation.Strategies.<>c__DisplayClass4.<Deactivate>b__3(Action`2 action) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Strategies\BindingActionStrategy.cs:42
   Ninject.Infrastructure.Language.ExtensionsForIEnumerableOfT.Map(IEnumerable`1 series, Action`1 action) in c:\Projects\Ninject\ninject\src\Ninject\Infrastructure\Language\ExtensionsForIEnumerableOfT.cs:32
   Ninject.Activation.Strategies.BindingActionStrategy.Deactivate(IContext context, InstanceReference reference) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Strategies\BindingActionStrategy.cs:42
   Ninject.Activation.<>c__DisplayClass6.<Deactivate>b__4(IActivationStrategy s) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Pipeline.cs:72
   Ninject.Infrastructure.Language.ExtensionsForIEnumerableOfT.Map(IEnumerable`1 series, Action`1 action) in c:\Projects\Ninject\ninject\src\Ninject\Infrastructure\Language\ExtensionsForIEnumerableOfT.cs:32
   Ninject.Activation.Pipeline.Deactivate(IContext context, InstanceReference reference) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Pipeline.cs:72
   Ninject.Activation.Caching.Cache.Forget(CacheEntry entry) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Caching\Cache.cs:253
   Ninject.Activation.Caching.Cache.Forget(IEnumerable`1 cacheEntries) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Caching\Cache.cs:242
   Ninject.Activation.Caching.Cache.Clear(Object scope) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Caching\Cache.cs:197
   Ninject.Web.Common.<>c__DisplayClass2.<DeactivateInstancesForCurrentHttpRequest>b__1(IKernel kernel) in c:\Projects\Ninject\Ninject.Web.Common\src\Ninject.Web.Common\OnePerRequestHttpModule.cs:74
   Ninject.GlobalKernelRegistration.MapKernels(Action`1 action) in c:\Projects\Ninject\ninject\src\Ninject\GlobalKernelRegistration.cs:75
   Ninject.Web.Common.OnePerRequestHttpModule.DeactivateInstancesForCurrentHttpRequest() in c:\Projects\Ninject\Ninject.Web.Common\src\Ninject.Web.Common\OnePerRequestHttpModule.cs:74
   Ninject.Web.Common.OnePerRequestHttpModule.<Init>b__0(Object o, EventArgs e) in c:\Projects\Ninject\Ninject.Web.Common\src\Ninject.Web.Common\OnePerRequestHttpModule.cs:56
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +136
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69

编辑-更详细的

此错误将在对RegisterOnEventBroker的调用中设置的禁用委托中引发，其中代码试图注销在事件代理上注册的任何对象。它失败是因为事件代理作用域已被释放，可能是因为父服务已被释放。据我所知，Ninject只会调用OnDeactivation委托对象的生命周期以外的短暂作用域，所以为什么这不能工作，当父服务是在RequestScope中注册使我感到困惑。对于父服务来说，瞬态作用域是不够的，因为由于这个问题，我正在经历内存泄漏。

我开始怀疑这是否是EventBroker扩展中的一个bug。

Answer 1

首先必须将IParentService绑定到ParentService，然后使用具体类型kernel.Bind<ParentService>().ToSelf()的自绑定来定义对象范围和事件代理。

    private static void RegisterServices(IKernel kernel)
    {
        kernel.Bind<IParentService>().To<ParentService>();


        kernel.Bind<ParentService>().ToSelf()
       .InRequestScope()
       .OwnsEventBroker("ParentServiceBroker")
       .RegisterOnEventBroker("ParentServiceBroker");

        kernel.DefineDependency<IParentService, ChildService>();
        kernel.Bind<ChildService>().ToSelf()
            .WhenInjectedInto<ParentService>()
            .InDependencyCreatorScope()
            .RegisterOnEventBroker("ParentServiceBroker"); 
    }    

编辑：--如果您解析的类型是具体类型(如上面的ParentService )，Ninject将通过一种名为隐式自绑定的机制自动创建默认关联。如下所示：

 kernel.Bind<ParentService>().ToSelf();

另一方面，隐式自绑定是在默认对象范围(即Transient )中生成的。这就是为什么您的代码不在Request作用域中运行的原因。

有关更多信息，请参见这里

编辑2:

bbvEventBroker扩展在Request作用域中存在一个缺陷，导致在处理在该EventBroker上注册的对象之前释放了EventBroker。因此，在对象的OnDeactivation方法中，不存在可以调用其注销寄存器并抛出ScopeDisposedException wan的EventBroker。

    public static IBindingOnSyntax<T> OwnsEventBroker<T>(this IBindingOnSyntax<T> syntax, string eventBrokerName)
    {
        string namedScopeName = "EventBrokerScope" + eventBrokerName;
        syntax.DefinesNamedScope(namedScopeName);
        syntax.Kernel.Bind<IEventBroker>().To<EventBroker>().InNamedScope(namedScopeName).Named(eventBrokerName);
        syntax.Kernel.Bind<IEventBroker>().ToMethod(ctx => ctx.ContextPreservingGet<IEventBroker>(eventBrokerName)).WhenTargetNamed(eventBrokerName);
        return syntax;
    }

您可以在OwnsEventBroker方法中看到NamedScope在对象的作用域(ParentService)中定义，它强制它在对象(ParentService)之前进行释放。

另一方面，在OnDeactivation of the object (ParentService)中，需要更早地释放EventBroker。

    public static IBindingOnSyntax<T> RegisterOnEventBroker<T>(
        this IBindingOnSyntax<T> syntax, string eventBrokerName)
    {
        return
            syntax.OnActivation((ctx, instance) => ctx.ContextPreservingGet<IEventBroker>(eventBrokerName).Register(instance))
                  .OnDeactivation((ctx, instance) => ctx.ContextPreservingGet<IEventBroker>(eventBrokerName).Unregister(instance));
    }

EventBrokerExtensionMethods.cs

解决方案是使用NamedScope创建对象树。在Request作用域中定义父级，同时为其子级(Publisher/订户)定义一个NamedScope，并拥有事件代理(OwnsEventBroker)。然后由父级定义命名范围中的发布服务器(ChildService1)和订阅服务器(ChildService2)。通过这种方式，您可以确保事件代理的所有者将在他们的孩子之后被释放。

Answer 2

尼尼姆核心当前在禁用对象本身之前，先禁用对象的作用域中的对象。

改变订单似乎解决了这个问题。虽然在推动这一改变之前，我必须检查它对其他情况会产生什么样的副作用。