基于Unity容器中的对象生存期管理分析(3)

try
      {
        // exception - instance has been disposed with container
        example.SayHello();
      }
      catch (ObjectDisposedException ex)
      {
        Console.WriteLine(ex.Message);
      }

Console.ReadKey();
    }

ExternallyControlledLifetimeManager

ExternallyControlledLifetimeManager中的对象实例的生存期限将有UnityContainer外部的实现控制。此生存期管理器内部直存储了所提供对象实例的一个WeakReference。所以如果UnityContainer容器外部实现中没有对该对象实例的强引用，则该对象实例将被GC回收。再次请求该对象类型实例时，将会创建新的对象实例。

复制代码 代码如下:

private static void TestExternallyControlledLifetimeManager()
    {
      IExample example;
      using (IUnityContainer container = new UnityContainer())
      {
        container.RegisterType(typeof(IExample), typeof(Example),
          new ExternallyControlledLifetimeManager());

// same instance is used in following
        container.Resolve<IExample>().SayHello();
        container.Resolve<IExample>().SayHello();

// run garbate collector. Stored Example instance will be released
        // beacuse there is no reference for it and LifetimeManager holds
        // only WeakReference       
        GC.Collect();

// object stored targeted by WeakReference was released
        // new instance is created!
        container.Resolve<IExample>().SayHello();
        example = container.Resolve<IExample>();
      }

example.SayHello();

Console.ReadKey();
    }

这个结果证明强引用还存在，不知道为什么？如果你找到了原因，烦请告诉我，谢谢。

PerThreadLifetimeManager

PerThreadLifetimeManager模型提供“每线程单实例”功能。所有的对象实例在内部被存储在ThreadStatic的集合。容器并不跟踪对象实例的创建并且也不负责Dipose。

复制代码 代码如下:

private static void TestPerThreadLifetimeManager()
    {
      IExample example;
      using (IUnityContainer container = new UnityContainer())
      {
        container.RegisterType(typeof(IExample), typeof(Example),
          new PerThreadLifetimeManager());

Action<int> action = delegate(int sleep)
        {
          // both calls use same instance per thread
          container.Resolve<IExample>().SayHello();
          Thread.Sleep(sleep);
          container.Resolve<IExample>().SayHello();
        };

Thread thread1 = new Thread((a) => action.Invoke((int)a));
        Thread thread2 = new Thread((a) => action.Invoke((int)a));
        thread1.Start(50);
        thread2.Start(50);

thread1.Join();
        thread2.Join();

example = container.Resolve<IExample>();
      }

example.SayHello();

Console.ReadKey();
    }

PerResolveLifetimeManager