第21章线程

水深无声 2021-06-24 16:11 368阅读 0赞

使用Thread类可以创建和控制线程。

## 基础应用 ##

using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    
    namespace Threading
    {
        class Program
        {
            static void Main(string[] args)
            {
                var t1 = new Thread(ThreadMain);
                t1.Start();
                Console.WriteLine("This is the main thread.");
                Task.Run(() => { Console.WriteLine("Runing in the second thread."); });
                Console.ReadLine();
            }
            static void ThreadMain()
            {
                Console.WriteLine("Runing in a thread.");
            }
        }
    }

![2789632-7ef4b8e83dfc4589.png][]

## task与thread的异同（答案收集于百度）： ##

task是根据自己需要调用线程,thread就是个基本单位；  
thread是单核多线程，task是多核多线程；  
直接用Thread做多线程和 用Task目前还是看不出太大的区别；  
Task对象需要更多的内存，但任务运行的更快；  
从网上百度了一个比较task，thread，threadpool效率的代码：

using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    
    namespace Threading
    {
        static class Program
        {
            static void Main(string[] args)
            {
                for (var i = 1; i <= 50; i++)
                    TestTask(i);
                for (var i = 1; i <= 50; i++)
                    TestThreadPool(i);
                for (var i = 1; i <= 50; i++)
                    TestThread(i);
                Console.ReadLine();
            }
    
            private static void TestThread(int i)
            {
                Console.WriteLine("Thread {0} start.", i);
                new Thread(h =>
                {
                    Thread.Sleep(5000);
                    Console.WriteLine("-------------------Thread {0} end.", i);
                }).Start();
            }
    
            private static void TestThreadPool(int i)
            {
                Console.WriteLine("ThreadPool {0} start.", i);
                ThreadPool.QueueUserWorkItem(h =>
                {
                    Thread.Sleep(5000);
                    Console.WriteLine("-------------------ThreadPool {0} end.", i);
                });
            }
    
            private static void TestTask(int i)
            {
                Console.WriteLine("Task {0} start.", i);
                new Task(() =>
                {
                    Thread.Sleep(5000);
                    Console.WriteLine("-------------------Task {0} end.", i);
                }).Start();
            }
        }
    }

由下图可见，thread相对速度要快一些。不知道这样比较是片面的，以后还要多多留意。

![2789632-6180f3885cfae701.png][]

[2789632-7ef4b8e83dfc4589.png]: /images/20210615/69b46286e83b444081728f0a6297d7bd.png
[2789632-6180f3885cfae701.png]: /images/20210615/46685389da2f4eda8b749eb70c79a690.png