c# 线程，同步，锁

最近在阅读《c#高级编程》 这本书。记录一下关于锁的使用

大致分为三种方法：

方法1：使用 lock

方法2：使用 Interlocked

方法3：使用 Monitor

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int numTasks = 20;
            var state = new SharedState();
            var tasks = new Task[numTasks];
 
            for (int i = 0; i < numTasks; i++)
            {
                tasks[i] = Task.Run(() => new Job(state).DoTheJob());
            }
 
            for (int i = 0; i < numTasks; i++)
            {
                tasks[i].Wait();
            }
            Console.WriteLine("summarized {0}", state.State);
            Console.ReadLine();
        }
    }
 
    public class SharedState
    {
        private int state = 0;
        private object syncRoot = new object();
 
        public int State
        {
            get { return state; }
        }
 
        public int IncrementState()
        {
            //方法1：使用interlocked
            //return Interlocked.Increment(ref state);
            //方法2：使用lock
            //lock (syncRoot)
            //{
            //    state++;
            //    return state;
            //}
            //方法3：使用Monitor
            Monitor.Enter(syncRoot);
            try
            {
                state++;
                return state;
            }
            finally
            {
                Monitor.Exit(syncRoot);
            }
 
            //Monitor的其他用法：等待超过超时时间就不等了
            //bool lockTaken = false;
            //Monitor.TryEnter(syncRoot, 500, ref lockTaken);
            //if (lockTaken)
            //{
            //    try
            //    {
            //        //do something
            //    }
            //    finally
            //    {
            //        Monitor.Exit(syncRoot);
            //    }
            //}
            //else//未获得锁
            //{
            //    //do something else
            //}
        }
    }
    public class Job
    {
        SharedState sharedState;
        public Job(SharedState sharedState)
        {
            this.sharedState = sharedState;
        }
        public void DoTheJob()
        {
            for (int i = 0; i < 5000; i++)
            {
                sharedState.IncrementState();
            }
        }
    }
}