using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace MemRelease
{
    class Program
    {
        ~Program()
        {
            // Orders.
        }
        static void Main(string[] args)
        {
        }
    }
}

.method family hidebysig virtual instance void
        Finalize() cil managed
{
  // Code size       14 (0xe)
  .maxstack  1
  .try
  {
    IL_0000:  nop
    IL_0001:  nop
    IL_0002:  leave.s    IL_000c
  }  // end .try
  finally
  {
    IL_0004:  ldarg.0
    IL_0005:  call       instance void [mscorlib]System.Object::Finalize()
    IL_000a:  nop
    IL_000b:  endfinally
  }  // end handler
  IL_000c:  nop
  IL_000d:  ret
} // end of method Program::Finalize

public class Foo: IDisposable
 {
     public void Dispose()
     {
        Dispose(true);
        GC.SuppressFinalize(this);
     }
     protected virtual void Dispose(bool disposing)
     {
        if (!m_disposed)
        {
            if (disposing)
            {
               // Release managed resources
            }
            // Release unmanaged resources
            m_disposed = true;
        }
     }
     ~Foo()
     {
        Dispose(false);
     }
     private bool m_disposed;
 }

namespace 资源回收
{
    class Program
    {
        static void Main(string[] args)
        {
            //使用using对实现IDisposable的类了进行资源管理
/*拿到一个对象的时候，首先判断这个对象是否实现了IDisposable接口，如果实现了，最好就用using包裹住这个对象，保证这个对象用完之后被释放掉，否则很可能出现资源泄露的问题
*/
            using (Telphone t1 = new Telphone())
            {
                t1.Open();
                t1.Speak("hello");
                t1.Bomb();
                //t1.Dispose();//如果在这里调用了Dispose()方法释放资源，那么在执行t1.Open()方法就出错，电话线已经被剪断了，无法再打电话了
                t1.Open();
                t1.Speak("I am back!");
            }//代码执行到这里后，就会调用Dispose方法来进行资源回收
            Console.ReadKey();
        }
    }
    /// <summary>
    /// Telphone类实现了IDisposable接口
    /// </summary>
    class Telphone : IDisposable
    {
        /// <summary>
        /// 电话状态
        /// </summary>
        private TelphoneState state;
        /// <summary>
        /// 打电话
        /// </summary>
        public void Open()
        {
            if (state == TelphoneState.Disposed)
            {
                throw new Exception("电话线已经被剪断，无法打开！");
            }
            state = TelphoneState.Open;
            Console.WriteLine("拿起电话");
        }
        /// <summary>
        /// 说话
        /// </summary>
        /// <param name="s">说话内容</param>
        public void Speak(string s)
        {
            if (state != TelphoneState.Open)
            {
                throw new Exception("没有连接");
            }
            Console.WriteLine(s);
        }
        /// <summary>
        /// 挂掉电话
        /// </summary>
        public void Bomb()
        {
            state = TelphoneState.Close;
            Console.WriteLine("挂掉电话");
        }
        IDisposable 成员
    }
    /// <summary>
    /// 电话状态枚举
    /// </summary>
    enum TelphoneState
    {
        Open, Close, Disposed
    }
}

public class ResourceHolder : IDisposable
{
      private bool isDispose ＝ false;
      // 显示调用的Dispose方法
　 public void Dispose()
      {
           Dispose(true);
          GC.SuppressFinalize(this);
       }
       // 实际的清除方法
　 protected virtual void Dispose(bool disposing)
      {
            if (!isDisposed)
           {
      　       if (disposing)
　　         {
                      // 这里执行清除托管对象的操作.
                  }
                  // 这里执行清除非托管对象的操作
            }
　        isDisposed=true;
      }
      // 析构函数
      ~ResourceHolder()
      {
            Dispose (false);
      }
}