c# - 为什么 Autofac 不调用我的类' `Dispose()` ？

Question

下面的代码有一个非常简单的演示，其中的组件实现了IDisposable。不幸的是，实际上没有一个析构函数被调用。谁能告诉我为什么？

using System;
using System.Collections.Generic;
using Autofac;

namespace AutofacDemos
{
  public interface ILog : IDisposable
  {
    void Write(string message);
  }

  public class ConsoleLog : ILog
  {
    public void Write(string message)
    {
      Console.WriteLine(message);
    }

    // needed for demonstrating ExternallyOwned()
    public void Dispose()
    {
      Console.WriteLine("Console logger no longer required");
    }
  }

  public class Engine
  {
    private readonly ILog log;

    public Engine(ILog log)
    {
      this.log = log;
    }

    public void Ahead(int power)
    {
      log.Write($"Engine ahead {power}");
    }
  }

  public class Car : IDisposable
  {
    private readonly Engine engine;
    private readonly ILog log;

    public Car(Engine engine)
    {
      this.engine = engine;
    }

    // constructor with most arguments used by default
    public Car(Engine engine, ILog log)
    {
      this.engine = engine;
      this.log = log;
    }

    public void Go()
    {
      engine.Ahead(100);
      log.Write("Car going forward...");
    }


    public void Dispose()
    {
      log.Dispose();
    }
  }

  internal class Program
  {
    public static void Main(string[] args)
    {
//      var log = new ConsoleLog();
//      var engine = new Engine(log);
//      var car = new Car(engine, log); // dependencies

      var builder = new ContainerBuilder();
      //builder.RegisterType<ConsoleLog>().As<ILog>();
      var log = new ConsoleLog();
      builder.RegisterInstance(log).As<ILog>().ExternallyOwned();

      //builder.RegisterType<Engine>();
      builder.RegisterType(typeof(Engine));

      builder.RegisterType<Car>();

      // use the engine-only constructor
      //builder.RegisterType<Car>().UsingConstructor(typeof(Engine));

      //builder.RegisterTypes(typeof(Car), typeof(Engine));

      var container = builder.Build();

      var car = container.Resolve<Car>();

      using (container.BeginLifetimeScope())
      {
        car.Go();
      }


    }
  }
}

Answer 1

您应该从生命周期范围而不是容器中解析您的服务。试试这个:

using (var scope = container.BeginLifetimeScope())
{
    var car = scope.Resolve<Car>();
    car.Go();
}