C#多线程---Task实现异步

一、场景

使用Task来进行累加操作。

二、例子-Task使用

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

namespace AsyncTask
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.ForegroundColor = ConsoleColor.DarkGreen;
            PrintThreadInfo("Print info in Main");
            Console.ResetColor();
            Console.WriteLine();
            Task<int> myTask = new Task<int>(loop => AsyncMethod((int)loop), 10);
            myTask.Start();
            Console.WriteLine($"Result is: {myTask.Result}");//myTask.Result会阻塞当前调用线程
            Console.WriteLine("Done!");
        }
        private static int AsyncMethod(int loopNum)
        {
            PrintThreadInfo("Print info in AsyncMethod");
            int mySum = 0;
            for(int i = 0; i < loopNum; i++)
            {
                mySum += i;
                Thread.Sleep(1000);
            }
            return mySum;
        }
        private static void PrintThreadInfo(string info)
        {
            Console.WriteLine(info);
            Console.WriteLine($"ThreadId:{Thread.CurrentThread.ManagedThreadId}
IsBackgroundThread:{Thread.CurrentThread.IsBackground}
IsThreadPoolThread:{Thread.CurrentThread.IsThreadPoolThread}");
            int workerThread = 0;
            int ioThread = 0;
            ThreadPool.GetMaxThreads(out workerThread, out ioThread);
            Console.WriteLine($"MaxWorkerThread:{workerThread}
MaxIoThread:{ioThread}");
            int workerThreadAvailable = 0;
            int ioThreadAvailable = 0;
            ThreadPool.GetAvailableThreads(out workerThreadAvailable, out ioThreadAvailable);
            Console.WriteLine($"AvailableWorkerThread:{workerThreadAvailable}
AvailableIoThread:{ioThreadAvailable}");
        }
    }
}

注：myTask.Result会阻塞当前调用线程

运行结果如下：

三、例子-Task取消

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

namespace AsyncTask
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.ForegroundColor = ConsoleColor.DarkGreen;
            PrintThreadInfo("Print info in Main");
            Console.ResetColor();
            Console.WriteLine();
            CancellationTokenSource cts = new CancellationTokenSource();
            Task<int> myTask = new Task<int>(loop => AsyncMethod((int)loop,cts.Token), 10);
            myTask.Start();

            //Thread.Sleep(3000);
            //cts.Cancel();
            cts.CancelAfter(3 * 1000);
            Console.WriteLine($"Result is: {myTask.Result}");//myTask.Result会阻塞当前调用线程
            Console.WriteLine("Done!");
        }
        private static int AsyncMethod(int loopNum, CancellationToken ct)
        {
            PrintThreadInfo("Print info in AsyncMethod");
            int mySum = 0;
            try {
                for (int i = 0; i < loopNum; i++)
                {
                    ct.ThrowIfCancellationRequested();
                    mySum += i;
                    Thread.Sleep(1000);
                }
            }
            catch(Exception e)
            {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("Exception type:" + e.GetType().Name);
                Console.WriteLine("Operation is Canceled");
                Console.ResetColor();
            }
            return mySum;
        }
        private static void PrintThreadInfo(string info)
        {
            Console.WriteLine(info);
            Console.WriteLine($"ThreadId:{Thread.CurrentThread.ManagedThreadId}
IsBackgroundThread:{Thread.CurrentThread.IsBackground}
IsThreadPoolThread:{Thread.CurrentThread.IsThreadPoolThread}");
            int workerThread = 0;
            int ioThread = 0;
            ThreadPool.GetMaxThreads(out workerThread, out ioThread);
            Console.WriteLine($"MaxWorkerThread:{workerThread}
MaxIoThread:{ioThread}");
            int workerThreadAvailable = 0;
            int ioThreadAvailable = 0;
            ThreadPool.GetAvailableThreads(out workerThreadAvailable, out ioThreadAvailable);
            Console.WriteLine($"AvailableWorkerThread:{workerThreadAvailable}
AvailableIoThread:{ioThreadAvailable}");
        }
    }
}

运行结果如下：

四、例子-Task工厂

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

namespace AsyncTask
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.ForegroundColor = ConsoleColor.DarkGreen;
            PrintThreadInfo("Print info in Main");
            Console.ResetColor();
            Console.WriteLine();
            CancellationTokenSource cts = new CancellationTokenSource();
            //Task<int> myTask = new Task<int>(loop => AsyncMethod((int)loop,cts.Token), 10);
            //myTask.Start();

            Task<int> myTask = Task.Factory.StartNew(loop => AsyncMethod((int)loop, cts.Token), 10);

            //Thread.Sleep(3000);
            //cts.Cancel();
            cts.CancelAfter(3 * 1000);
            Console.WriteLine($"Result is: {myTask.Result}");//myTask.Result会阻塞当前调用线程
            Console.WriteLine("Done!");
        }
        private static int AsyncMethod(int loopNum, CancellationToken ct)
        {
            PrintThreadInfo("Print info in AsyncMethod");
            int mySum = 0;
            try {
                for (int i = 0; i < loopNum; i++)
                {
                    ct.ThrowIfCancellationRequested();
                    mySum += i;
                    Thread.Sleep(1000);
                }
            }
            catch(Exception e)
            {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("Exception type:" + e.GetType().Name);
                Console.WriteLine("Operation is Canceled");
                Console.ResetColor();
            }
            return mySum;
        }
        private static void PrintThreadInfo(string info)
        {
            Console.WriteLine(info);
            Console.WriteLine($"ThreadId:{Thread.CurrentThread.ManagedThreadId}
IsBackgroundThread:{Thread.CurrentThread.IsBackground}
IsThreadPoolThread:{Thread.CurrentThread.IsThreadPoolThread}");
            int workerThread = 0;
            int ioThread = 0;
            ThreadPool.GetMaxThreads(out workerThread, out ioThread);
            Console.WriteLine($"MaxWorkerThread:{workerThread}
MaxIoThread:{ioThread}");
            int workerThreadAvailable = 0;
            int ioThreadAvailable = 0;
            ThreadPool.GetAvailableThreads(out workerThreadAvailable, out ioThreadAvailable);
            Console.WriteLine($"AvailableWorkerThread:{workerThreadAvailable}
AvailableIoThread:{ioThreadAvailable}");
        }
    }
}