简单多线程 非安全实例 与 解决方法

多线程 非安全实例

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading;

namespace ThreadSample

{

    class Program

    {

        static void Main(string[] args)

        {

            int numThreads = 20;

            ShareState state = new ShareState();

            Thread[] threads = new Thread[numThreads];

            for (int i = 0; i < numThreads; i++)

            {

                threads[i] = new Thread(new Task(state).DoTheTask);

                threads[i].Start();

            }

            for (int i = 0; i < numThreads; i++)

            {

              threads[i].Join();  

            }

            Console.WriteLine("ShareState.State最后结果是:" + state.State);

            Console.ReadLine();

        }

    }

    public class Task

    {

        ShareState shareState;

        public Task(ShareState shareState)

        {

            this.shareState = shareState;

        }

        public void DoTheTask()

        {

            ///设为5000，数据大点更能 看到线程非安全的效果

            for (int i = 0; i < 5000; i++)

            {

                shareState.State += 1;

            }

        }

    }

    public class ShareState

    {

        public int State { get; set; }

    }



}

 

解决方法的实例

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

namespace ThreadSample02
{
    class Program
    {
        static void Main(string[] args)
        {
            int numThreads = 20;
            ShareState state = new ShareState();
            Thread[] threads = new Thread[numThreads];
            for (int i = 0; i < numThreads; i++)
            {
                threads[i] = new Thread(new Task(state).DoTheTask);
                threads[i].Start();
            }
            for (int i = 0; i < numThreads; i++)
            {
                threads[i].Join();
            }
            Console.WriteLine("ShareState.State最后结果是:" + state.State);
            Console.ReadLine();
        }
    }
    public class Task
    {
        ShareState shareState;
        public Task(ShareState shareState)
        {
            this.shareState = shareState;
        }
        public void DoTheTask()
        {
            ///设为5000，数据大点更能 看到线程非安全的效果
            for (int i = 0; i < 5000; i++)
            {
                lock (shareState)
                {
                    shareState.State += 1;
                }
            }
        }
    }
    public class ShareState
    {
        public int State { get; set; }
    }
}