基于Unity容器中的对象生存期管理分析(2)

ContainerControlledLifetimeManager将为UnityContainer及其子容器提供一个Singleton的注册类型对象实例。其只在第一次请求某注册类型时创建一个新的对象实例，该对象实例将被存储到生存期管理器中，并且一直被重用。当容器析构时，生存期管理器会调用RemoveValue将存储的对象销毁。

Singleton对象实例对应每个对象类型注册，如果同一对象类型注册多次，则将为每次注册创建单一的实例。

复制代码 代码如下:

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

IUnityContainer firstSub = null;
        IUnityContainer secondSub = null;

try
        {
          firstSub = container.CreateChildContainer();
          secondSub = container.CreateChildContainer();

// all containers share same instance
          // each resolve returns same instance
          firstSub.Resolve<IExample>().SayHello();

// run one resolving in other thread and still receive same instance
          Thread thread = new Thread(
            () => secondSub.Resolve<IExample>().SayHello());
          thread.Start();

container.Resolve<IExample>().SayHello();
          example = container.Resolve<IExample>();
          thread.Join();
        }
        finally
        {
          if (firstSub != null) firstSub.Dispose();
          if (secondSub != null) secondSub.Dispose();
        }
      }

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

Console.ReadKey();
    }

HierarchicalLifetimeManager类衍生自ContainerControlledLifetimeManager，其继承了父类的所有行为。与父类的不同之处在于子容器中的生存期管理器行为。ContainerControlledLifetimeManager共享相同的对象实例，包括在子容器中。而HierarchicalLifetimeManager只在同一个容器内共享，每个子容器都有其单独的对象实例。

复制代码 代码如下:

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

IUnityContainer firstSub = null;
        IUnityContainer secondSub = null;

try
        {
          firstSub = container.CreateChildContainer();
          secondSub = container.CreateChildContainer();

// each subcontainer has its own instance
          firstSub.Resolve<IExample>().SayHello();
          secondSub.Resolve<IExample>().SayHello();
          container.Resolve<IExample>().SayHello();
          example = firstSub.Resolve<IExample>();
        }
        finally
        {
          if (firstSub != null) firstSub.Dispose();
          if (secondSub != null) secondSub.Dispose();
        }
      }