MSDN中的AutoResetEvent构造函数中的示例代码

[zhiheyang]

下面是msdn中AutoResetEvent构造函数中的示例代码：

using System;
using System.Threading;

namespace AutoResetEvent_Examples
{
	class MyMainClass
	{
		//Initially not signaled.
      const int numIterations = 100;
      static AutoResetEvent myResetEvent = new AutoResetEvent(false);
      static int number;

      static void Main()
		{
         //Create and start the reader thread.
         Thread myReaderThread = new Thread(new ThreadStart(MyReadThreadProc));
         myReaderThread.Name = "ReaderThread";
         myReaderThread.Start();

         for(int i = 1; i <= numIterations; i++)
         {
            Console.WriteLine(">>{0}", i);
            number = i;

            //Signal that a value has been written.
            myResetEvent.Set();

            //Give the Reader thread an opportunity to act.
            Thread.Sleep(0);
         }

         //Terminate the reader thread.
         myReaderThread.Abort();
      }

      static void MyReadThreadProc()
      {
         while(true)
         {
            //The value will not be read until the writer has written
            // at least once since the last read.
            myResetEvent.WaitOne();
            Console.WriteLine("    <<{0}",number);
         }
      }
	}
}

但是当我把写数据线程中的2句代码换下顺序时，就可能会出现读线程读出同一个数据的情况。
就是把

for(int i = 1; i <= numIterations; i++)
         {
            Console.WriteLine(">>{0}", i);
            number = i;

            //Signal that a value has been written.
            myResetEvent.Set();

            //Give the Reader thread an opportunity to act.
            Thread.Sleep(0);
         }

改为

for(int i = 1; i <= numIterations; i++)
         {
            number = i;
            Console.WriteLine(">>{0}", i);
            //Signal that a value has been written.
            myResetEvent.Set();

            //Give the Reader thread an opportunity to act.
            Thread.Sleep(0);
         }

时，就有可能出现读线程读出同一个数据的情况。

请问这是什么原因？

[zhiheyang]

怎么没人那

[TimZhuFaith]

帮顶。。。我也想知道答案！可能分低了。。

[zhiheyang]

半天也没人回答啊，加分

[缭绕飘渺]

没看出问题所在
单步跟踪下应该能够发现吧

[abrianna]

测试过。没问题。

[abrianna]

using System;
using System.Threading;

namespace AutoResetEvent_Examples
{
    class MyMainClass
    {
        //Initially not signaled.
        const int numIterations = 100;
        static AutoResetEvent myResetEvent = new AutoResetEvent(false);
        static int number;

        static void Main()
        {
            //Create and start the reader thread.
            Thread myReaderThread = new Thread(new ThreadStart(MyReadThreadProc));
            myReaderThread.Name = "ReaderThread";
            myReaderThread.Start();

            for (int i = 1; i <= numIterations; i++)
            {
                number = i;
                Console.WriteLine(">>{0}", i);
                System.IO.File.AppendAllText("testlog02.txt", string.Format(">>{0}", i));
                

                //Signal that a value has been written.
                myResetEvent.Set();

                //Give the Reader thread an opportunity to act.
                Thread.Sleep(0);
            }

            //Terminate the reader thread.
            myReaderThread.Abort();
            Console.ReadKey();
        }

        static void MyReadThreadProc()
        {
            while (true)
            {
                //The value will not be read until the writer has written
                // at least once since the last read.
                myResetEvent.WaitOne();
                Console.WriteLine("    <<{0}", number);
            }
        }
    }
}

using System;
using System.Threading;

namespace AutoResetEvent_Examples
{
    class MyMainClass
    {
        //Initially not signaled.
        const int numIterations = 100;
        static AutoResetEvent myResetEvent = new AutoResetEvent(false);
        static int number;

        static void Main()
        {
            //Create and start the reader thread.
            Thread myReaderThread = new Thread(new ThreadStart(MyReadThreadProc));
            myReaderThread.Name = "ReaderThread";
            myReaderThread.Start();

            for (int i = 1; i <= numIterations; i++)
            {
                 Console.WriteLine(">>{0}", i);
                 number = i;
                 System.IO.File.AppendAllText("testlog01.txt", string.Format(">>{0}", i));
                

                //Signal that a value has been written.
                myResetEvent.Set();

                //Give the Reader thread an opportunity to act.
                Thread.Sleep(0);
            }

            //Terminate the reader thread.
            myReaderThread.Abort();
            Console.ReadKey();
        }

        static void MyReadThreadProc()
        {
            while (true)
            {
                //The value will not be read until the writer has written
                // at least once since the last read.
                myResetEvent.WaitOne();
                Console.WriteLine("    <<{0}", number);
            }
        }
    }
}

两次，生成的内容存文件中，然后对比文件，没任何不同。

[zhiheyang]

[Quote=引用 7 楼 abrianna 的回复:]

C# code
using System;
using System.Threading;

namespace AutoResetEvent_Examples
{
class MyMainClass
{
//Initially not signaled.
const int numIterations = 100;
static……
[/Quote]

不能这么测吧，生成的文件里写的都是写的数据，写的数据肯定没问题啊，要看的是读线程读出来的数据

[abrianna]

so?
你问题是什么？这个例子很简单，就是循环打印屏幕。哪来的读数据？

[zhiheyang]

[Quote=引用 9 楼 abrianna 的回复:]

so?
你问题是什么？这个例子很简单，就是循环打印屏幕。哪来的读数据？
[/Quote]
我说的读数据就是把数据打印在屏幕上

msdn说的这个例子不会将重复的数据打印在屏幕上，但我换了那两行代码后就会出现重复的数据

[zhiheyang]

靠，不会上图
结果如下：
<<81
>>81
<<81

[abrianna]

无满意答案结帖

楼主，我鄙视你到天荒地老。

对得起我给你测试不？自己不懂就否定别人回答。