Autofac，ASP.NET MVC 3 HttpRequest的范围和AutoMapper：不带标签匹配“的HttpRequest”范围可见

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：Autofac，ASP.NET MVC 3 HttpRequest的范围和AutoMapper：不带标签匹配“的HttpRequest”范围可见

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.

当其他类型在其映射中起作用时被解析。当网络类型从控制器中解析出来后，它就可以工作。

为什么不能在我的映射中成功解析web（或任何其他httprequest作用域？）类型？

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 
{ 
}

编辑：它很容易创建一个空MVC项目，粘贴代码，并尝试一下，看看自己。

编辑：删除了ConstructServicesUsing调用，因为它不是示例所要求的。在本例中没有通过AutoMapper解决任何服务。

答

我想你应该在

Mapper.Initialize(c => 
       {        
        c.ConstructServicesUsing(DependencyResolver.Current); 
        profiles.ToList().ForEach(c.AddProfile); 
       });

这并不甚至编译，但它改变到\t \t \t \t \t \t \t \t \t c.ConstructServicesUsing（DependencyResolver.Current.GetService）;它编译，但它仍然是同样的问题。 – MatteS

答

@rene_r使用DependencyResolver.Current.Resolve代替container.Resolve以上是在正确的轨道上;适应他的回答：

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

仍然可能不会编译，但应该让你关闭。

的要求是调用DependencyResolver.Current将被推迟到服务请求（不保持当映射器被初始化由Current返回的值。）

当我评论rene_r时，它仍然没有解决问题。 – MatteS

完全删除了调用，因为它使它没有什么不同，我不认为它真的很重要，因为在示例中没有通过automapper解决服务。 – MatteS

'var profiles = container.Resolve >（）;'不起作用 - 'MyProfile'依赖于每个请求类型的'HttpContext'（'Func'不会改变这个）。 –

答

我最近也有类似的问题，它横空出世在我的引导程序功能中是一个糟糕的设置。以下autofac设置为我做了。

builder.Register(c => new ConfigurationStore(new TypeMapFactory(), AutoMapper.Mappers.MapperRegistry.Mappers)) 
    .AsImplementedInterfaces() 
    .SingleInstance(); 

builder.Register(c => Mapper.Engine) 
    .As<IMappingEngine>() 
    .SingleInstance(); 

builder.RegisterType<TypeMapFactory>() 
    .As<ITypeMapFactory>() 
    .SingleInstance();

我没有在Mapper.Initialize（）函数来指定解析器。刚刚叫

Mapper.Initialize(x => 
      { 
       x.AddProfile<DomainToDTOMappingProfile>(); 
      });

引导后，它适用于我很好。

Autofac，ASP.NET MVC 3 HttpRequest的范围和AutoMapper：不带标签匹配“的HttpRequest”范围可见

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