29:         }

  30:  

  31:         Thread.Sleep(5000);

  32:     }

  33: }

好了，现在公司实体有了，老板就可以开始忙活了：

   1: static void Main(string args)

   2: {

   3:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "WuDaokou", To = "LinDa Road", Fee = 500 });

   4:  

   5:     while (HouseMovingCompany.Instance.Contracts.Count > 0)

   6:     {

   7:         HouseMovingCompany.Instance.MoveHouse();

   8:     }

   9: }

我们在前面设置了每次搬家耗时5秒钟，咱们把它想象成5个小时。嗯，一天接一个单子，还可以接受，但是随着老板生意日渐兴隆，有时候一天要接3个单子，这就最少要工作15个小时了，还要操心公司的运营等问题，的确忙不过来了，而且照这样算，老板一天不可能完成5个或5个以上的单子，严重制约了公司的发展：

   1: static void Main(string args)

   2: {

   3:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "WuDaokou", To = "LinDa Road", Fee = 500 });

   4:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "XiDan", To = "WangFujing", Fee = 1000 });

   5:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "XiangShan", To = "The Forbidden City", Fee = 10000 });

   6:  

   7:     while (HouseMovingCompany.Instance.Contracts.Count > 0)

   8:     {

   9:         HouseMovingCompany.Instance.MoveHouse();

  10:     }

  11: }

一天夜里，老板拖着疲倦的身子回到家里，一进门就一头倒在床上，他极力睁着快睁不开的眼睛，努力地对自己说：“不行，我一定要想个办法，不然我会被累死的！”。

其实办法很简单，谁都知道，招聘几个员工，再买几辆车，大家分头行动，不仅分担了工作负担，而且在规模扩大的同时还可以完成更多更大的单子。好，我们现在就借助多线程机制来实现我们的想法：

   1: static void Main(string args)

   2: {

   3:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "WuDaokou", To = "LinDa Road", Fee = 500 });

   4:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "XiDan", To = "WangFujing", Fee = 1000 });

   5:     HouseMovingCompany.Instance.Contracts.Add(new Contract { From = "XiangShan", To = "The Forbidden City", Fee = 10000 });

   6:  

   7:     Thread thread = null;

   8:  

   9:     while (HouseMovingCompany.Instance.Contracts.Count > 0)

  10:     {

  11:         thread = new Thread(new ThreadStart(HouseMovingCompany.Instance.MoveHouse));

  12:  

  13:         thread.Start();

  14:     }

  15: }

在这段程序中，我们分头行动，让每项搬家任务都由一个小团队去完成，结果我们发现，现在做三个单子的时间跟做一个单子的时间是一样的，提高了效率也扩大了公司规模。但是，既然引入了新的工作机制，我们在公司内部也不得不做一些小小的调整：

   1: public void MoveHouse()

   2: {

   3:     if (this.Contracts == null || this.Contracts.Count == 0)

   4:     {

   5:         return;

   6:     }

   7:  

   8:     Contract contract = null;

   9:  

  10:     lock (this.Contracts)

  11:     {

  12:         contract = this.Contracts[0];

  13: