通过Task异步加快对数组的运算

一.介绍

  Task是.NetFramework3.0出现的，线程是基于线程池，然后提供了丰富的API. 先用AverageAssign方法把一组数据平均分成n组，再通过遍历n组数据，循环开Task多线程。

二.平均分组方法

        /// <summary>
        /// 将一组数据平均分成n组
        /// </summary>
        /// <param name="source">要分组的数据源</param>
        /// <param name="n">平均分成n组</param>
        /// <returns><T></returns>
        public static List<List<T>> AverageAssign(List<T> source, int n)
        { 
            List<List<T>> result = new List<List<T>>();
            int remainder = source.Count() % n;  //(先计算出余数)
            int number = source.Count() / n;  //然后是商
            int offset = 0;//偏移量
            for (int i = 0; i < n; i++)
            {
                List<T> value = null;
                if (remainder > 0)
                { 
                    value = source.Take((i + 1) * number + offset + 1).Skip(i * number + offset).ToList();
                    remainder--;
                    offset++;
                }
                else
                { 
                    value = source.Take((i + 1) * number + offset).Skip(i * number + offset).ToList();
                }
                result.Add(value);
            }
            return result;
        }

三.Task

           string message = string.Empty;
            var listGroup =  Test<ModelDemo>.AverageAssign(list,3);
            //信号量
            var tokenSource = new CancellationTokenSource();
            //先添加进Task数组,然后一起启动异步
            //TaskFactory taskFactory = new TaskFactory();
            //List<Task> taskList = new List<Task>();
            //taskList.Add(taskFactory.StartNew(() =>
            //{}
            // Task.WaitAll(taskList.ToArray());
            try
            {

                foreach (var group in listGroup)
                {
                    Task.Factory.StartNew(() =>
                    {
                        if (tokenSource.Token.IsCancellationRequested)
                        {
                            Console.WriteLine("日志");
                            return;
                        }

                        //要执行的方法
                        Print(group);

                    }, tokenSource.Token);
                     
                }
                 
            }
            catch (AggregateException aex)
            {
                tokenSource.Cancel();
                foreach (var item in aex.InnerExceptions)
                {
                    message += item.Message;
                }
                Console.WriteLine(message);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

static void Print(List<ModelDemo> model)
{
  foreach (var item in model)
  {
    Console.WriteLine(item.Id);
  }
}

四.源码

 https://github.com/gyw1309631798/MyTask