Autofac解析相同类型的多个实例

我的应用程序中有一个稍微修改的Mediatr处理命令处理版本。我实现了MediatorPipeline，使我可以使用前置和后置处理器。

public class AsyncMediatorPipeline<TRequest, TResponse> 
    : IAsyncRequestHandler<TRequest, TResponse> 
    where TRequest : IAsyncRequest<TResponse>
{
    private readonly IAsyncRequestHandler<TRequest, TResponse> inner;
    private readonly IAsyncPreRequestHandler<TRequest>[] preRequestHandlers;
    private readonly IAsyncPostRequestHandler<TRequest,TResponse>[] postRequestHandlers;

    public AsyncMediatorPipeline(IAsyncRequestHandler<TRequest, TResponse> inner, 
        IAsyncPreRequestHandler<TRequest>[] preRequestHandlers, 
        IAsyncPostRequestHandler<TRequest, TResponse>[] postRequestHandlers)
    {
        this.inner = inner;
        this.preRequestHandlers = preRequestHandlers;
        this.postRequestHandlers = postRequestHandlers;
    }

    public async Task<TResponse> Handle(TRequest message)
    {
        foreach (var preRequestHandler in preRequestHandlers)
        {
            await preRequestHandler.Handle(message);
        }

        var result = await inner.Handle(message);

        foreach (var postRequestHandler in postRequestHandlers)
        {
            await postRequestHandler.Handle(message, result);
        }

        return result;
    }
}

我正在用autofac注册我的预处理器，如下所示：

builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly())
    .As(type => type.GetInterfaces()
        .Where(type => type.IsClosedTypeOf(typeof(IAsyncPreRequestHandler<>))))
    .InstancePerLifetimeScope();

在运行时，我得到了重复的前任。我必须过滤删除重复项的集合。我不确定为什么会这样。如果我注释掉注册，则不会得到任何预处理程序，这表明我没有在其他地方复制注册。

更新：这是有关似乎已两次注册的类型的更多详细信息。各种类定义：

具体处理程序

public class ClientEditorFormIdentifierValidationHandler 
: IAsyncPreRequestHandler<AddOrEditClientCommand>{}

命令类

public class AddOrEditClientCommand 
: IAsyncRequest<ICommandResult>{}

命令界面

public interface IAsyncRequest<out TResponse> { }