一、简介

Semaphore类限制可同时访问某一资源或资源池的线程数。线程通过调用 WaitOne方法将信号量减1，并通过调用 Release方法把信号量加1。

构造函数：public Semaphore(int initialCount,int maximumCount);通过两个参数来设置信号的初始计数和最大计数。

二、例子

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading; 6 using System.Threading.Tasks; 7  8 namespace ThreadMutex 9 {10     class Program11     {12         private static Mutex mutex = new Mutex();13         private static Semaphore semaphore = new Semaphore(3, 10);14         private static int sum = 0;15         static void Main(string[] args)16         {17             for (int i = 0; i < 10; i++)18             {19                 Task
      
        task = new Task
       
        (ThreadFunction);20                 task.Start();21             }22             Console.WriteLine($"{DateTime.Now} task started!");23             Console.Read();24 25         }26         private static int ThreadFunction()27         {28             Thread.Sleep(100);29             if(semaphore.WaitOne(2000))30             {31                 Console.WriteLine($"Thread {Thread.CurrentThread.ManagedThreadId} get semaphore successed!");32             }33             else34             {35                 Console.WriteLine($"Thread {Thread.CurrentThread.ManagedThreadId} get semaphore failed!");36             }37           38             return sum;39         }40     }41 }
       
      

运行结果如下：