Question

我正在使用ASP.Net MVC为后端构建应用程序。 Autofac用于依赖注入。几个组件/类注册为InstancePerRequest。实体框架上下文和工作单元（只是一个调用context.SaveChanges()的包装器）注册为InstancePerLifetimeScope。示例代码：

builder.RegisterAssemblyTypes(Assembly.GetAssembly(typeof(DomainModule)))
    .Where(t => t.IsClosedTypeOf(typeof(IFooService<>)))
    .AsImplementedInterfaces()
    .AsClosedTypesOf(typeof(IFoo<>))
    .InstancePerRequest();

builder.RegisterType<FooContext>()
    .AsSelf()
    .As<IObjectContextAdapter>()
    .InstancePerLifetimeScope();

builder.RegisterType<UnitOfWork>()
    .AsImplementedInterfaces()
    .AsSelf()
    .InstancePerLifetimeScope();

使用显式范围从容器中解析类会引发以下异常：

{"No scope with a Tag matching 'AutofacWebRequest' is visible from the scopein which the instance was requested. This generally indicates that a component registered as per-HTTP request is being requested by a SingleInstance() component (or a similar scenario.) Under the web integration always request dependencies from the DependencyResolver.Current or ILifetimeScopeProvider.RequestLifetime, never from the container itself."}

触发上述异常的代码：

using (var scope = _lifetimeScope.BeginLifetimeScope())
{
    var authOrchestration = scope.Resolve<IAuthOrchestration>();
    apiClient = authOrchestration.GetApiClient(context.ClientId);
}

请注意，IAuthOrchestration未注册InstancePerRequest之类的内容，因此应默认为InstancePerDependency。

我现在一直试图绕过这个问题几个小时。我已阅读these two篇文章。从我读过的内容来看，我认为由于范围不匹配而抛出异常（如here所述）。如果有人能够解释我为什么会收到这个错误，我会非常感激。

非常感谢提前。

Answer 1

IAuthOrchestration对IFoo有间接依赖关系，注册为InstancePerHttpRequest。要（直接或间接）解决IFoo您必须使用请求 ILifetimeScope

您创建的ILifetimeScope不是RequestLifetimeScope。要创建此类ILifetimeScope，您可以使用MatchingScopeLifetimeTags。RequestLifetimeScope`标记。

using (var scope = _lifetimeScope
                    .BeginLifetimeScope(MatchingScopeLifetimeTags.RequestLifetimeScopeTag))
{
    var authOrchestration = scope.Resolve<IAuthOrchestration>();
    apiClient = authOrchestration.GetApiClient(context.ClientId);                
}

Autofac无法解析课程

1 个答案: