Autofac，ASP.NET MVC 3 HTT prequest范围和AutoMapper：一个标签匹配'HTT prequest“没有范围是可见 [英] Autofac, ASP.NET MVC 3 httpRequest scope and AutoMapper: No scope with a Tag matching 'httpRequest' is visible

问题描述

当我用从automapper映射autofac注册的网络类型，我得到这个错误：

When I use a web type registered with autofac from an automapper mapping, I get this error:

没有一个标签匹配'HTT prequest'的范围是其中要求该实例的范围可见。这通常表示登记为每个HTTP请求的组件是由一个SingleInstance（）成分reqested（或类似的情形。）在幅积分总是请求从DependencyResolver.Current或ILifetimeScopeProvider.RequestLifetime依赖关系，不会从容器本身

No scope with a Tag matching 'httpRequest' is visible from the scope in which the instance was requested. This generally indicates that a component registered as per-HTTP request is being reqested 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.

在另一种类型是在它工作的映射解决。
当网络类型是从它的工作原理控制器解决。

When another type is resolved in the mapping it works. When a web type is resolved from the controller it works.

为什么犯规网页（或任何其他HTT prequest范围？）类型得到我的映射成功解决？

Why doesnt web (or any other httprequest scoped?) types get successfully resolved in my mapping?

    protected void Application_Start()
    {
        var builder = new ContainerBuilder();
        builder.RegisterModule<AutofacWebTypesModule>();
        builder.RegisterControllers(Assembly.GetExecutingAssembly());
        builder.RegisterModelBinders(Assembly.GetExecutingAssembly());
        builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly())
            .AssignableTo<Profile>()
            .As<Profile>()
            ;
        builder.Register(c => Mapper.Engine)
            .As<IMappingEngine>();
        builder.RegisterType<AnotherType>()
            .As<IAnotherType>();
        var container = builder.Build();

        DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

        var profiles = container.Resolve<IEnumerable<Profile>>();
        Mapper.Initialize(c => profiles.ToList().ForEach(c.AddProfile));

        AreaRegistration.RegisterAllAreas();

        RegisterGlobalFilters(GlobalFilters.Filters);
        RegisterRoutes(RouteTable.Routes);
    }

public class HomeController : Controller
{
    private readonly IMappingEngine _mapper;
    private readonly Func<HttpContextBase> _httpContext;

    public HomeController(IMappingEngine mapper, Func<HttpContextBase> httpContext)
    {
        _mapper = mapper;
        _httpContext = httpContext;
    }

    public ActionResult Index()
    {
        var test = _httpContext.Invoke();
        return View(_mapper.Map<Model, ViewModel>(new Model()));
    }

}

public class MyProfile : Profile
{
    private readonly Func<HttpContextBase> _httpContext;
    private readonly Func<IAnotherType> _anotherType;

    public MyProfile(Func<HttpContextBase> httpContext, Func<IAnotherType> anotherType)
    {
        _httpContext = httpContext;
        _anotherType = anotherType;
    }

    protected override void Configure()
    {
        CreateMap<Model, ViewModel>()
            .ForMember(d => d.Url, o => o.ResolveUsing(s =>
                                                    {
                                                        var test = _anotherType.Invoke().GetAValue();
                                                        return _httpContext.Invoke().Request.Url;
                                                    }))
            ;
    }
}

public interface IAnotherType
{
    string GetAValue();
}

public class AnotherType : IAnotherType
{
    public string GetAValue() { return "a value"; }
}

public class ViewModel
{
    public string Url { get; set; }
}

public class Model
{
}

修改：它很容易创建一个空MVC项目，粘贴code，并尝试一下，看看自己

EDIT: Its easy to create an empty MVC project, paste the code and try it out and see for yourself.

修改：删除了ConstructServicesUsing调用，因为它不是由例子必需的。没有服务是通过AutoMapper在本例中得到解决。

EDIT: Removed the ConstructServicesUsing call because its not required by the example. No services are resolved through AutoMapper in the example.

推荐答案

@rene_r上面是正确的轨道上;适应他的回答：

@rene_r above is on the right track; adapting his answer:

c.ConstructServicesUsing(t => DependencyResolver.Current.GetService(t))

不过可能无法编译，但应该让你关闭。

Still might not compile but should get you close.

的要求是调用直到服务请求（不保留由的返回值电流 DependencyResolver.Current 被推迟code>当映射器被初始化。）

The requirement is that the call to DependencyResolver.Current is deferred until the service is requested (not kept as the value returned by Current when the mapper was initialised.)

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