C#之：线程同步 Semaphore类和 SemaphoreSlim类

记一次SemaphoreSlim的使用

using System;
using System.Threading;

namespace ConsoleApp1
{
    public class Program2
    {
        #region Field(字段)

        private static SemaphoreSlim _semaphore = new SemaphoreSlim(4);

        #endregion Field(字段)

        #region Public Method（公开方法）

        private static void acquireSemaphore(string name, int seconds)
        {
            Console.WriteLine("{0} wait " + DateTime.Now, name);
            _semaphore.Wait();
            Console.WriteLine("{0} access " + DateTime.Now, name);
            Thread.Sleep(TimeSpan.FromSeconds(seconds));
            Console.WriteLine("{0} Release " + DateTime.Now, name);
            _semaphore.Release();
        }

        private static void Main(string[] args)
        {
            for (int i = 1; i <= 6; i++)
            {
                string threadName = "thread" + i;
                int secondsToWait = 2 + 2 * i;
                var t = new Thread(() => acquireSemaphore(threadName, secondsToWait));
                t.Start();
            }
            Console.ReadKey();
        }

        #endregion Public Method（公开方法）
    }
}

执行结果如下：

解释下：

SemaphoreSlim（4）限定最大入口并发数4，前面‘thread1’，‘thread2’，‘thread3’，‘thread5’四个线程先到，‘thread4’、‘thread6’后到进行等待，4秒后thread1释放，'thread6'进入，6秒后thread2释放，thread4进入。