简介4种同步方法的实现

问题重现

static void Main()

    {



      Thread[] theads = new Thread[10];

      Printer p = new Printer();

      for (int i = 0; i < 10; i++)

      {

        theads[i] = new Thread(new ThreadStart(p.DisplayDigites));

        theads[i].Name = string.Format("thread work: {0}", i);

      }



      foreach (Thread t in theads)

        t.Start();

    }

新建一个Printer类，

public class Printer

  {

    public void DisplayDigites()

    {

      Console.WriteLine("{0} is executing DisplayDigites", Thread.CurrentThread.Name);

      Console.Write("Your Number are:");

      for (int i = 0; i < 10; i++)

      {



        Console.Write("{0},", i);

      }

      Console.WriteLine();



    }

  }

得到结果是：

很明显 这不是我们想要的结果。可能原因很多人都知道，是因为同步问题。那我们怎么解决这个同步问题呢？下面有4种方法，可以选择。

一。使用C#的lock 关键字

我们只需要在输出的方法上面加上lock 关键字就可以了。

 public void DisplayDigites()

    {

      lock (this)

      {

        Console.WriteLine("{0} is executing DisplayDigites", Thread.CurrentThread.Name);

        Console.Write("Your Number are:");

        for (int i = 0; i < 10; i++)

        {

          Console.Write("{0},", i);

        }

      }

      Console.WriteLine();

    }

得到的结果是：

这样就得到了我们的期望。当然 更常见的是，我们需要定义一个常见来替换this，如下表示：

private object obj = new object();

    public void DisplayDigites()

    {

      lock (obj)

      {

        Console.WriteLine("{0} is executing DisplayDigites", Thread.CurrentThread.Name);

        Console.Write("Your Number are:");

        for (int i = 0; i < 10; i++)

        {

          Console.Write("{0},", i);

        }

      }

      Console.WriteLine();

    }

结果也是一样。

二。使用Monitor进行同步

 private object obj = new object();

    public void DisplayDigites()

    {

      Monitor.Enter(obj);

      try

      {

        Console.WriteLine("{0} is executing DisplayDigites", Thread.CurrentThread.Name);

        Console.Write("Your Number are:");

        for (int i = 0; i < 10; i++)

        {

          Console.Write("{0},", i);

        }

      }

      finally

      {

        Monitor.Exit(obj);

      }

      Console.WriteLine();

    }

  }

三。使用[Synchronization]特性进行同步

这个很简单，只需要把这个特性添加到类上面就好了。但是还需要实现ContextBoundObject。。实现code 如下：

[Synchronization]

  public class Printer:ContextBoundObject

  {

    public void DisplayDigites()

    {

      Console.WriteLine("{0} is executing DisplayDigites", Thread.CurrentThread.Name);

      Console.Write("Your Number are:");

      for (int i = 0; i < 10; i++)

      {

        Console.Write("{0},", i);

      }

      Console.WriteLine();

    }

  }