Autofac 无法从远程程序集中解析对象（转换为已知类型）

Question

这是我的 WCF(vs2015@net452) autofac (v4.6.1) 设置：

MyService.dll:

builder.Register(c => (ISession)RemoteObjectFactory.GetInstance(typeof(MySessionBase))).As<ISession>().SingleInstance();
...
var session = AutofacHostFactory.Container.Resolve<ISession>();

<Message>An exception was thrown while executing a resolve operation. See the InnerException for details.
Could not load file or assembly "MyRemotingHost, Version=1.0.6442.29085, Culture=neutral, PublicKeyToken=null" or one of its dependencies. File not found(See inner exception for details.)</Message>
<StackTrace>at Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable`1 parameters)&#xD;
at Autofac.ResolutionExtensions.TryResolveService(IComponentContext context, Service service, IEnumerable`1 parameters, Object&amp; instance)&#xD;
at Autofac.ResolutionExtensions.ResolveService(IComponentContext context, Service service, IEnumerable`1 parameters)&#xD;
at Autofac.ResolutionExtensions.Resolve[TService](IComponentContext context, IEnumerable`1 parameters)&#xD;
at My.DoSomeWork() at C:\Projects\...
<Type>Autofac.Core.DependencyResolutionException</Type>

MyService.dll指的是MyDefs.dll.

MyRemotingHost.dll指的是MyDefs.dll.

MyService.dll 通过远程调用 MyRemotingHost.dll。 RemoteObjectFactory.GetInstance 是一种包装方法，returns（通过远程处理）从 MyRemotingHost.dll.

到 MySession 对象的透明代理

抽象 class MySessionBase 实现 ISession。两者都在 MyDefs.dll.

中定义

Class MySession 是 MySessionBase 的子类，在 MyRemotingHost.dll.

中定义

严格来说MyService.dll不知道MyRemotingHost.dll也不应该知道。为什么 autofac 会尝试获取有关此远程程序集的信息？

更新

ISession session = (MySessionBase)RemoteObjectFactory.GetInstance(typeof(MySessionBase));
builder.RegisterInstance(session);

RegisterInstance 抛出同样的错误。

更新2 第二次（及后续）解决尝试 不抛出 奇怪的错误。

builder.Register(c => (ISession)RemoteObjectFactory.GetInstance(typeof(MySessionBase))).As<ISession>().SingleInstance();
...
var session1 = AutofacHostFactory.Container.Resolve<ISession>();
var session2 = AutofacHostFactory.Container.Resolve<ISession>();

行 var session1 = ... 抛出错误。如果错误被抑制，那么下一行 var session2 = ... 不会产生错误。

基于 PDB 的逐步调试显示在第一次调用枚举器时，错误源位于 foreach 循环内的 Autofac.Core.Resolving.ResolveOperation：

private void CompleteActivations()
{
    var completed = _successfulActivations;
    ResetSuccessfulActivations();

    foreach (var activation in completed)
        activation.Complete();
}

我无法进行更多调查，因为我坚持使用 VS2015，而 autofac 源已经具有 VS2017 格式。

Answer 1

问题出在 log4net autofac module:

var instanceType = instance.GetType();

在该行之前添加检查可解决问题：

// cant use GetType() on TransparentProxy as it may throw error
if (RemotingServices.IsTransparentProxy(instance)) return;

Autofac 无法从远程程序集中解析对象（转换为已知类型）

Autofac fails to initailly resolve object from remote assembly (cast to know type)

c#

wcf

remoting

dependency-injection

autofac