C#多线程---ReaderWriterLock实现线程同步

一、简介

当我们需要对一个共享资源多次读取的时候，用前面Monitor的同步锁就没有必要了。因为同步锁每次只允许一个线程访问共享资源，其他线程都会阻塞。

此时，通过ReaderWriterLock类可以很好的实现读取并行。

二、例子

using System;
using System.Threading;

namespace ThreadMonitor
{
    class Program
    {
        private static object lockObj = new object();
        private static ReaderWriterLock readerwritelock = new ReaderWriterLock();
        static void Main(string[] args)
        {
            for (int i = 0; i < 10; i++)
            {
                Thread testthread = new Thread(Add);
                testthread.IsBackground = true;
                testthread.Start();
            }

            for (int i = 0; i < 10; i++)
            {
                Thread testthread2 = new Thread(Read);
                testthread2.IsBackground = true;
                testthread2.Start();
            }
            Console.WriteLine("All thread created done!");
            Console.Read();
        }

        // 共享资源
        public static int number = 1;

        public static void Add()
        {    
            //Monitor.Enter(lockObj);  //获得排他锁,每次只有一个线程可以进入
            readerwritelock.AcquireWriterLock(50000);
            Console.ForegroundColor = ConsoleColor.DarkGreen;     
            Console.WriteLine($"{DateTime.Now} CurrentThreadIDAdd:{Thread.CurrentThread.ManagedThreadId} CurrentValue:{number++}" );
            Thread.Sleep(2000); 
            Console.ResetColor();
            //Monitor.Exit(lockObj);
            readerwritelock.ReleaseWriterLock();

        }
        public static void Read()
        {     
            //Monitor.Enter(lockObj);      //获得排他锁
            readerwritelock.AcquireReaderLock(50000);
            Console.ForegroundColor = ConsoleColor.DarkRed;
            Console.WriteLine($"{DateTime.Now} CurrentThreadIDRead:{Thread.CurrentThread.ManagedThreadId} CurrentValue:{number}");
            Thread.Sleep(2000);
            Console.ResetColor();
            readerwritelock.ReleaseReaderLock();
            //Monitor.Exit(lockObj);// 释放指定对象上的排他锁。
      
        }
    }
}

运行结果如下：