Task使用（入门级）

【核心代码】

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

namespace TaskTest
{
    class Program
    {
        static void Main(string[] args)
        {
            #region Task的状态
            //var task1 = new Task(() =>
            //{
            //    Console.WriteLine("Begin");
            //    System.Threading.Thread.Sleep(2000);
            //    Console.WriteLine("Finish");
            //});
            //Console.WriteLine("Before start:"   task1.Status);
            //task1.Start();
            //Console.WriteLine("After start:"   task1.Status);
            //task1.Wait();
            //Console.WriteLine("After Finish:"   task1.Status);

            //Console.Read();
            #endregion

            #region 多任务执行
            //var task1 = new Task(() =>
            //{
            //    Console.WriteLine("Task 1 Begin");
            //    System.Threading.Thread.Sleep(2000);
            //    Console.WriteLine("Task 1 Finish");
            //});
            //var task2 = new Task(() =>
            //{
            //    Console.WriteLine("Task 2 Begin");
            //    System.Threading.Thread.Sleep(3000);
            //    Console.WriteLine("Task 2 Finish");
            //});

            //task1.Start();
            //task2.Start();
            //Task.WaitAll(task1, task2);
            //Console.WriteLine("All task finished!");

            //Console.Read();
            #endregion

            #region 等待任一个任务执行完毕
            //var task1 = new Task(() =>
            //{
            //    Console.WriteLine("Task 1 Begin");
            //    System.Threading.Thread.Sleep(2000);
            //    Console.WriteLine("Task 1 Finish");
            //});
            //var task2 = new Task(() =>
            //{
            //    Console.WriteLine("Task 2 Begin");
            //    System.Threading.Thread.Sleep(3000);
            //    Console.WriteLine("Task 2 Finish");
            //});

            //task1.Start();
            //task2.Start();
            //Task.WaitAny(task1, task2);
            //Console.WriteLine("All task finished!");

            //Console.Read();
            #endregion

            #region 一个Task执行完成之后执行另一个Task
            //var task1 = new Task(() =>
            //{
            //    Console.WriteLine("Task 1 Begin");
            //    System.Threading.Thread.Sleep(2000);
            //    Console.WriteLine("Task 1 Finish");
            //});
            //var task2 = new Task(() =>
            //{
            //    Console.WriteLine("Task 2 Begin");
            //    System.Threading.Thread.Sleep(3000);
            //    Console.WriteLine("Task 2 Finish");
            //});

            //task1.Start();
            //task2.Start();
            //var result = task1.ContinueWith<string>(task =>
            //{
            //    Console.WriteLine("task1 finished!");
            //    return "This is task result!";
            //});

            //Console.WriteLine(result.Result.ToString());
            //Console.Read();
            #endregion
            #region TaskContinuationOptions使用
            //Task<Int32> t = new Task<Int32>(i => Sum((Int32)i), 10000);

            //t.Start();

            //t.ContinueWith(task => Console.WriteLine("The sum is:{0}", task.Result),
            //    TaskContinuationOptions.OnlyOnRanToCompletion);

            //t.ContinueWith(task => Console.WriteLine("Sum throw:"   task.Exception),
            //    TaskContinuationOptions.OnlyOnFaulted);

            //t.ContinueWith(task => Console.WriteLine("Sum was cancel:"   task.IsCanceled),
            //    TaskContinuationOptions.OnlyOnCanceled);
            //try
            //{
            //    t.Wait();  // 测试用
            //}
            //catch (AggregateException)
            //{
            //    Console.WriteLine("出错");
            //}
            //Console.Read();
            #endregion


            Task<Int32[]> parent = new Task<Int32[]>(() => {
                var results = new Int32[3];
                //
                new Task(() => results[0] = Sum(10000), TaskCreationOptions.AttachedToParent).Start();
                new Task(() => results[1] = Sum(20000), TaskCreationOptions.AttachedToParent).Start();
                new Task(() => results[2] = Sum(30000), TaskCreationOptions.AttachedToParent).Start();
                return results;
            });

            var cwt = parent.ContinueWith(parentTask => Array.ForEach(parentTask.Result, Console.WriteLine));


            parent.Start();
            cwt.Wait();
            Console.Read();
        }

        private static Int32 Sum(Int32 i)
        {
            Int32 sum = 0;
            for (; i > 0; i--)
            {
                checked { sum  = i; }
            }
            return sum;
        }
        
    }
}