Question

我正在尝试制作多线程应用程序。但输入只有一个线程。但我尝试用三个线程来制作它。这是该计划：

class MyThread
    {
        public int Count;
        public Thread Thrd;
        public MyThread(string name)
        {
            Count = 0;
            Thrd = new Thread(this.Run);
            Thrd.Name = name;
            Thrd.Start();
        }
        // Entry point of thread.
        void Run()
        {
            Console.WriteLine(Thrd.Name + " starting.");
            do
            {
                Thread.Sleep(500);
                Console.WriteLine("In " + Thrd.Name +
                ", Count is " + Count);
                Count++;
            } while (Count < 10);
            Console.WriteLine(Thrd.Name + " terminating.");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {

            Console.WriteLine("Main thread starting.");
            // Construct three threads.
            MyThread mt1 = new MyThread("Child #1");
            MyThread mt2 = new MyThread("Child #2");
            MyThread mt3 = new MyThread("Child #3");
            while (true)
            {
                Console.Write(".");
                Thread.Sleep(100);
                if (mt1.Count < 10 && mt2.Count < 10 &&  mt3.Count < 10)
                {
                    break; 
                }
                Console.WriteLine("Main thread ending.");
            }
            //do
            //{
            //    Console.Write(".");
            //    Thread.Sleep(100);
            //} 
            //while (mt1.Count < 10 && mt2.Count < 10 &&  mt3.Count < 10);
            //Console.WriteLine("Main thread ending.");
           // Console.ReadKey();
        }
    }

但输出是：见图片：

所以它只显示一个线程。而不是三个线程。

感谢你

这必须是输出：

Main thread starting.
.Child #1 starting.
Child #2 starting.
Child #3 starting.
....In Child #1, Count is 0
In Child #2, Count is 0
In Child #3, Count is 0
.....In Child #1, Count is 1
In Child #2, Count is 1
In Child #3, Count is 1
.....In Child #1, Count is 2
In Child #2, Count is 2
In Child #3, Count is 2
.....In Child #1, Count is 3
In Child #2, Count is 3
In Child #3, Count is 3
.....In Child #1, Count is 4
In Child #2, Count is 4
In Child #3, Count is 4
.....In Child #1, Count is 5
In Child #2, Count is 5
In Child #3, Count is 5
.....In Child #1, Count is 6
In Child #2, Count is 6
In Child #3, Count is 6
.....In Child #1, Count is 7
In Child #2, Count is 7
In Child #3, Count is 7
.....In Child #1, Count is 8
In Child #2, Count is 8
In Child #3, Count is 8
.....In Child #1, Count is 9
Child #1 terminating.
In Child #2, Count is 9
Child #2 terminating.
In Child #3, Count is 9
Child #3 terminating.
Main thread ending.

但如果我这样做：

static void Main(string[] args)
        {

            Console.WriteLine("Main thread starting.");
            // Construct three threads.
            MyThread mt1 = new MyThread("Child #1");
            MyThread mt2 = new MyThread("Child #2");
            MyThread mt3 = new MyThread("Child #3");
            //while (true)
            //{
            //    Console.Write(".");
            //    Thread.Sleep(100);
            //    if (mt1.Count < 10 && mt2.Count < 10 &&  mt3.Count < 10)
            //    {
            //        break; 
            //    }
            //    Console.WriteLine("Main thread ending.");
            //}
            do
            {
                Console.Write(".");
                Thread.Sleep(100);
            }
            while (mt1.Count < 10 && mt2.Count < 10 && mt3.Count < 10);
            Console.WriteLine("Main thread ending.");
            Console.ReadKey();
        }

它给出了相同的结果。

如果我这样做：

Console.WriteLine("Main thread starting.");
            // Construct three threads.
            MyThread mt1 = new MyThread("Child #1");
            MyThread mt2 = new MyThread("Child #2");
            MyThread mt3 = new MyThread("Child #3");

            mt1.Thrd.Join();
            mt2.Thrd.Join();
            mt3.Thrd.Join();

            do
            {
                Console.Write(".");
                Thread.Sleep(100);
            } while (mt1.Thrd.IsAlive &&  mt2.Thrd.IsAlive &&  mt3.Thrd.IsAlive);
            Console.WriteLine("Main thread ending.");

结果相同。只有一个帖子。

我这样试试：

  static void Main(string[] args)
        {
            Console.WriteLine("Main thread starting.");
            // Construct three threads.
            MyThread mt1 = new MyThread("Child #1");
            MyThread mt2 = new MyThread("Child #2");
            MyThread mt3 = new MyThread("Child #3");

            mt1.Thrd.Join();
            mt2.Thrd.Join();
            mt3.Thrd.Join();

            do
            {
                Console.Write(".");
                Thread.Sleep(100);
            } while (mt1.Count < 10 || mt2.Count < 10 || mt3.Count < 10);
            Console.WriteLine("Main thread ending.");

但结果仍然相同。

哦：

这对我有用!!

Console.WriteLine("Main thread starting.");
            // Construct three threads.
            MyThread mt1 = new MyThread("Child #1");
            MyThread mt2 = new MyThread("Child #2");
            MyThread mt3 = new MyThread("Child #3");

            mt1.Thrd.Join();
            mt2.Thrd.Join();
            mt3.Thrd.Join();

            do
            {
                Console.Write(".");
                Thread.Sleep(100);
            } while (mt1.Thrd.IsAlive || mt2.Thrd.IsAlive || mt3.Thrd.IsAlive);
            Console.WriteLine("Main thread ending.");

Answer 1

您正在创建三个课程。每个类都创建一个新线程，该线程递增其自己的属性。但是，如果所有数字小于10，那么您将退出控制台应用程序。换句话说，如果其中任何一个在其他数字之前达到10

while (mt1.Count < 10 && mt2.Count < 10 && mt3.Count < 10);

然后Main()将结束。在检查该条件之前，不能保证这些计数中的任何一个都达到10，更不用说所有这三个。其中一个甚至可以在其他人开始之前达到10个。

如果你改变它，你会更接近预期的影响：

while (mt1.Count < 10 || mt2.Count < 10 || mt3.Count < 10);

换句话说，如果中的任何一个小于10，那就继续吧。当他们都达到10时，停止。

您发现（或已经拥有）的其他内容是，除非您小心，否则多线程应用程序可能会以不可预测，不一致的方式运行。没有什么比一个99％的时间完美运行的程序更令人沮丧，但突然做了不同的事情，然后它再次按预期工作。 OptaPlanner您可以在其中测试并查看输出。

Answer 2

你所拥有的if语句是不正确的，根本不起作用。当我使用＆＃34; while＆＃34;版本，你的代码对我有用，除了你检测线程何时完成的策略是错误的（甚至可能是你的问题的来源）。试试这段代码，看看你的问题是否消失了。如果没有，那么您可能会遇到可用内存/ CPU /线程池本地问题。重新启动计算机，然后重试：）

static void Main(string[] args)
{
    Console.WriteLine("Main thread starting.");

    MyThread mt1 = new MyThread("Child #1");
    MyThread mt2 = new MyThread("Child #2");
    MyThread mt3 = new MyThread("Child #3");

    mt1.Thrd.Join();
    mt2.Thrd.Join();
    mt3.Thrd.Join();

    Console.WriteLine("Main thread ending.");
}

Answer 3

我找到了解决方案。看我的帖子

多线程，输出错误

3 个答案: