asp.net-mvc – Autofac：解决最内层范围的任何方法？

ILifetimeScope currentScope = ???;

using (var scope = currentScope.BeginLifetimeScope(cb => {
  cb.RegisterType<X>().InstancePerLifetimeScope();
  // ...
}))
{
    var comp = scope.Resolve<X>();
    // ...
}

在Autofac中,最里面的范围始终是容器.使用AutofacDependencyResolver,它就是
AutofacDependencyResolver.Current.ApplicationContainer

嵌套范围(如果你只有一个ILifetimeScope)无法“向后走”以到达容器.无论如何,我不一定确定你想这样做.

听起来你的SingleInstance组件正在做某种服务定位,基本上是通过手动注册/解析某些组件.如果注册的类型集是固定的,我可能会建议(如果可能的话)对系统进行一些重新设计,因此SingleInstance组件不再被注册为SingleInstance,而是被注册为InstancePerDependency,然后将这些其他项目作为构造函数参数.

代替…

// Consuming class like this...
public class BigComponent
{
  public void DoSomethingCool()
  {
    using(var scope = ...)
    {
      var c = scope.Resolve<SubComponent>();
      c.DoWork();
    }
  }
}

// ...and container registrations like this...
builder.RegisterType<BigComponent>().SingleInstance();

您可能会尝试反转一下：

// Consuming class like this...
public class BigComponent
{
  private SubComponent _c;
  public BigComponent(SubComponent c)
  {
    _c = c;
  }
  public void DoSomethingCool()
  {
    _c.DoWork();
  }
}

// ...and container registrations like this...
builder.RegisterType<BigComponent>().InstancePerDependency();
builder.RegisterType<SubComponent>().InstancePerLifetimeScope();

我们的想法是不必进行动态注册和即时解决的事情.

如果您遇到服务定位,如果您需要绝对最内层范围,则需要使用AutofacDependencyResolver.Current.ApplicationContainer,但请记住,如果您这样做,那么您注册为InstancePerHttpRequest的任何对象将无法解析,因此您可能会遇到麻烦.建议使用AutofacDependencyResolver.Current.RequestLifetimeScope.这会使你的方法：

var requestScope = AutofacDependencyResolver.Current.RequestLifetimeScope;
using (var scope = requestScope.BeginLifetimeScope(cb => {
  cb.RegisterType<X>().InstancePerLifetimeScope();
  // ...
}))
{
    var comp = scope.Resolve<X>();
    // ...
}

在测试环境中,AutofacDependencyResolver允许您交换指示如何生成请求生存期的提供程序.您可以实现这样的简单/存根：

public class TestLifetimeScopeProvider : ILifetimeScopeProvider
{
    readonly ILifetimeScope _container;
    private ILifetimeScope _lifetimeScope = null;

    public TestLifetimeScopeProvider(ILifetimeScope container)
    {
        if (container == null) throw new ArgumentNullException("container");
        _container = container;
    }

    public ILifetimeScope ApplicationContainer
    {
        get { return _container; }
    }

    public ILifetimeScope GetLifetimeScope()
    {
        if (_lifetimeScope == null)
        {
            _lifetimeScope = ApplicationContainer.BeginLifetimeScope("httpRequest")
        }
        return _lifetimeScope;
    }

    public void EndLifetimeScope()
    {
        if (_lifetimeScope != null)
            _lifetimeScope.Dispose();
    }
}

同样,只是用于单元测试的存根,而不是您在生产中使用的存根.

然后,当您在测试中连接DependencyResolver时,您将提供您的生命周期范围提供者：

var lsProvider = new TestLifetimeScopeProvider(container);
var resolver = new AutofacDependencyResolver(container,lsProvider);
DependencyResolver.SetResolver(resolver);

这使您可以使用InstancePerHttpRequest和此类内部单元测试,而无需实际具有实际请求上下文.这也意味着您应该能够在注册/解决方法中使用请求生命周期范围,而不必依赖于应用程序容器.