InstancePerRequest 的 MvcSiteMapProvider 和 Autofac 问题

Question

我已经安装了 nutget 包 MvcSiteMapProvider.MVC5.DI.Autofac.Modules。我正在尝试将我的 DBContext 注册为 InstancePerRequest。然而，这失败并出现错误

No scope with a Tag matching 'AutofacWebRequest' is visible from the scope in which the instance was requested.

如果我将 DBContext 更改为 InstancePerLifetimeScope，一切都很好。文件中抛出错误

DI\Autofac\Modules\MvcSiteMapProviderModule.cs    Line: 195

实际上，如果我尝试使用 InstancePerRequest 注册我自己的任何类型，我会收到此错误。我是 Autofac 的新手，所以不太了解 MvcSiteMapProvider Autofac 的 nuget 包中的很多代码。在我学习更多关于 Autofac 的同时，希望有人能指出正确的方向来解决这个问题？

编辑：

来自 Autofac 文档，我收到错误是因为：

Code is running during application startup (e.g., in an ASP.NET Global.asax) that uses dependency resolution when there isn’t an active request yet.

根据 MvcSiteMapProvider 文档，这一行是必需的，所以我可以将它移到其他地方吗？

// Setup global sitemap loader (required)
MvcSiteMapProvider.SiteMaps.Loader = container.Resolve<ISiteMapLoader>();

编辑 2：

protected void Application_Start()
{
    // BEGIN: Autofac Config
    var builder = new ContainerBuilder();

    builder.RegisterApiControllers(Assembly.GetExecutingAssembly());
    builder.RegisterControllers(typeof(MvcApplication).Assembly);
    builder.RegisterSource(new ViewRegistrationSource());

    // Register context and unit of work here
    IoC.Dependencies.Register.RegisterTypes(builder);

    builder.RegisterModule(new MvcSiteMapProviderModule());
    builder.RegisterModule(new MvcModule());

    var container = builder.Build();

    MvcSiteMapProvider.SiteMaps.Loader = container.Resolve<ISiteMapLoader>();

    GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(container);

    DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
    // END: Autofac Config

    Helpers.Log4NetManager.InitializeLog4Net();
    AreaRegistration.RegisterAllAreas();

    WebApiConfig.Register(GlobalConfiguration.Configuration);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);


    AntiForgeryConfig.UniqueClaimTypeIdentifier = ClaimTypes.NameIdentifier;
}

Answer 1

您正在使用 Autofac 注册您的控制器两次。

// This registers the all of the controllers in the application
builder.RegisterControllers(typeof(MvcApplication).Assembly);

// And so does this...
builder.RegisterModule(new MvcModule());

MvcModule 的内容：

public class MvcModule
    : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        var currentAssembly = typeof(MvcModule).Assembly;

        builder.RegisterAssemblyTypes(currentAssembly)
            .Where(t => typeof(IController).IsAssignableFrom(t))
            .AsImplementedInterfaces()
            .AsSelf()
            .InstancePerDependency();
    }
}

更新

来自 here:

The error pretty much says it all - something in your registrations has a dependency that is registered as InstancePerRequest and it's being resolved outside of a web request.

我不确定将 DBContext 注册为 InstancePerRequest 是个好主意。 MvcSiteMapProvider 在创建任何请求上下文之前加载，因此如果您使用动态节点提供程序或访问数据库的自定义 ISiteMapNodeProvider 实现，它将无法工作。更好的选择是使用不依赖于 HttpContext.

的 InstancePerDependency

Instance Per Dependency

在其他容器中也称为“transient”或“factory”。使用每个依赖范围，每个服务请求都会返回一个唯一的实例。

InstancePerRequest 的 MvcSiteMapProvider 和 Autofac 问题

MvcSiteMapProvider and Autofac issue with InstancePerRequest

c#

entity-framework

dependency-injection

autofac

mvcsitemapprovider

更新

Instance Per Dependency