多线程编程学习笔记——async和await

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

namespace ThreadAsyncDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(string.Format("-----    处理异步操作中的异常----"));
            Task t = AsyncProcess();
            t.Wait();       

            Console.Read();         

        } 

        async static Task AsyncProcess()
        {
            Console.WriteLine(string.Format("-----    1   单个异常处理----"));
            try
            {
               string result =await GetInfoAsync("Task 1", 2);
                Console.WriteLine(result);
            }
            catch (Exception ex)
            {
                Console.WriteLine(string.Format("异常信息：{0}",ex.Message));
            }

            Console.WriteLine(string.Format("                   -------   ----"));
            Console.WriteLine(string.Format("-----    2   多个异常处理----"));
            Task<string> task1 = GetInfoAsync("Task 1", 3);
            Task<string> task2 = GetInfoAsync("Task 2",2);
            try
            {
                string[] results = await Task.WhenAll(task1, task2);
                Console.WriteLine((string.Format("结果数量：{0}",results.Length)));
                foreach (var item in results)
                {
                    Console.WriteLine(item);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(string.Format("异常信息：{0}", ex.Message));
            }           

            Console.WriteLine(string.Format("                   -------   ----"));
            Console.WriteLine(string.Format("-----    3   多个异常处理 在AggregateException----"));
            Task<string> task3 = GetInfoAsync("Task 3", 3);
            Task<string> task4 = GetInfoAsync("Task 4", 2);
            Task<string[]> task5 = Task.WhenAll(task3, task4);
            try
            {
                string[] results5 = await task5;
                Console.WriteLine((string.Format("结果数量：{0}", results5.Length)));
                foreach (var item in results5)
                {
                    Console.WriteLine(item);
                }
            }
            catch
            {
                var aex = task5.Exception.Flatten(); //获取AggregateException
                var exs = aex.InnerExceptions;
                Console.WriteLine(string.Format("异常信息：{0}", exs.Count));
                int i = 0;
                foreach (var item in exs)
                {
                    i++;
                    Console.WriteLine(string.Format("       -----   {0}   ----",i));
                    Console.WriteLine(string.Format("异常信息：{0}", item.Message));
                }
            }
        } 

        async static Task<string> GetInfoAsync(string name,int second)
        {
            Console.WriteLine(string.Format(" Task {0} 正在运行在线程 ID={1}上。这个工作线程是否是线程池中的线程：{2}", name, 
Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread));
            await Task.Delay(TimeSpan.FromSeconds(second));
            throw new Exception(string.Format("{0} 抛出异常信息！", name));

        }
    }
}

 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms; 

namespace ThreadAsyncDemo
{
    public partial class FormContext : Form
    {
        public FormContext()
        {
            InitializeComponent();
        } 

        async static Task<TimeSpan> TestNoContext()
        {
            const int interationsNumber = 100000;
            var sw = new Stopwatch();
            sw.Start();
            for (int i = 0; i < interationsNumber; i++)
            {
                var t = Task.Run(() => { });
                await t.ConfigureAwait(continueOnCapturedContext: false);
            }

            sw.Stop();
            return sw.Elapsed;
        }
        async static Task<TimeSpan> Test()
        {
            const int interationsNumber = 100000;
            var sw = new Stopwatch();
            sw.Start();
            for (int i = 0; i < interationsNumber; i++)
            {
                var t = Task.Run(() => { });
                await t;
            }
            sw.Stop();
            return sw.Elapsed; 

        } 

        private async void buttonAsync_Click(object sender, EventArgs e)
        {
            textBoxMsg.Text = "程序开始计算。。。。";
            TimeSpan resultWithContext = await Test();
            TimeSpan resultNoContext = await TestNoContext();
            //TimeSpan resultNoContext = await TestNoContext().ConfigureAwait(false);
            var sb = new StringBuilder();
            sb.AppendLine(string.Format("有上下文的运行时间：{0}",resultWithContext));
            sb.AppendLine(string.Format("没有上下文的运行时间：{0}", resultNoContext));
            sb.AppendLine(string.Format("有上下文的运行时间/没有上下文的运行时间：{0:0.00}", 
resultWithContext.TotalMilliseconds/ resultNoContext.TotalMilliseconds));
            textBoxMsg.Text += "\r\n\r\n";
            textBoxMsg.Text += sb.ToString();
        }
    }
}