利用ManualResetEvent處理多執行緒同步作業

2020-07-29

利用設定ManualResetEvent的信號來控制多執行緒，等到多執行緒都同時完成某件事之後，才回到主要執行緒進行後續程式流程。這就是所謂的多執行緒同步

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

using System.Threading;

namespace ResetEventTest
{
    class Program
    {
        /*
         * reference:https://gmpg.org/xfn/11
         */

        private static ManualResetEvent mre_1 = new ManualResetEvent(false);
        private static ManualResetEvent mre_2 = new ManualResetEvent(false);

        static void Main(string[] args)
        {
            Console.WriteLine("\nStart 10 named threads that block on a ManualResetEvent:\n");

            for (int i = 0; i <= 10; i++)
            {
                Thread t = new Thread(ThreadProc_1);
                t.Name = /*"Thread_" +*/ i.ToString();
                t.Start();  //開始線程                
            }
            Thread.Sleep(10000);
            Console.WriteLine("\n Waiting for 10Seconds..... \n");
            
            
            for (int i = 11; i <= 13; i++)
            {
                Thread t = new Thread(ThreadProc_2);
                t.Name = /*"Thread_" +*/ i.ToString();
                t.Start();  //開始線程
            }
            Thread.Sleep(120000);
            Console.WriteLine("\n Waiting for 120Seconds..... \n");               
        }

        private static void ThreadProc_1()
        {
            string name = Thread.CurrentThread.Name;
            Console.WriteLine("Thread " + name + " starts and calls mre.WaitOne()");
            if (Convert.ToInt16(name) % 2 == 0)
            {                
                mre_2.WaitOne();//執行緒2.4.6.8.10綁定mre_2，並阻塞MRE       
            }
            else
            {                
                mre_1.Set();//執行緒1.3.5.7.9綁定mre_1，開啟mre_1綠燈
            }
            Console.WriteLine("Thread " + name + " end mre.WaitOne()");
        }

        private static void ThreadProc_2()
        {
            string name = Thread.CurrentThread.Name;
            Console.WriteLine("Thread " + name + " starts and calls mre.WaitOne()");
            if (Convert.ToInt16(name) % 2 == 0)
            {
                mre_2.Set();//執行緒12綁定mre_2，開啟mre_2綠燈。執行緒2.4.6.8.10繼續執行line55
            }
            else
            {
                mre_1.Set();//執行緒11.13綁定mre_1，開啟mre_1綠燈
            }
            Console.WriteLine("Thread " + name + " end mre.WaitOne()");
        }
    }
}

執行結果：