.Net(C#) Parallel.For和Parallel.Invoke介绍及使用方法

1、Parallel.For()方法

Parallel.For(int fromInclude, int toExclude, Action body)

与for循环类似，执行并行的循环，相当于每次循环一个线程

官方文档：https://docs.microsoft.com/zh-cn/dotnet/api/system.threading.tasks.parallel.for?redirectedfrom=MSDN&view=netframework-4.7.2

Parallel.For(0, 10, (i) => {    Console.Write(i);});

完整示例代码：

using System;using System.Threading;using System.Threading.Tasks;public class Example{   public static void Main()   {      var rnd = new Random();      int breakIndex = rnd.Next(1, 11);      Nullable lowest = new Nullable();      Console.WriteLine("Will call Break at iteration {0}\n",                        breakIndex);      var result = Parallel.For(1, 101, (i, state) => {                                            Console.WriteLine("Beginning iteration {0}", i);                                            int delay;                                            Monitor.Enter(rnd);                                               delay = rnd.Next(1, 1001);                                            Monitor.Exit(rnd);                                            Thread.Sleep(delay);                                                                                        if (state.ShouldExitCurrentIteration) {                                               if (state.LowestBreakIteration < i)                                                  return;                                            }                                            if (i == breakIndex) {                                               Console.WriteLine("Break in iteration {0}", i);                                               state.Break();                                               if (state.LowestBreakIteration.HasValue)                                                  if (lowest < state.LowestBreakIteration)                                                     lowest = state.LowestBreakIteration;                                                  else                                                     lowest = state.LowestBreakIteration;                                            }                                            Console.WriteLine("Completed iteration {0}", i);                                       });         if (lowest.HasValue)            Console.WriteLine("\nLowest Break Iteration: {0}", lowest);         else            Console.WriteLine("\nNo lowest break iteration.");   }}

2、Parallel.Invoke()方法

Parallel.Invoke(ParallelOptions, Action[])

对给定任务实现并行执行

官方文档：https://docs.microsoft.com/zh-cn/dotnet/api/system.threading.tasks.parallel.invoke?redirectedfrom=MSDN&view=netframework-4.7.2

var all = new [] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
Parallel.ForEach(all, (i) => {
    Console.Write($"{i} ");
});

完整示例代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;using System.Threading.Tasks;    class ParallelInvokeDemo    {

        //显示功能:        // Parallel.Invoke()        //预期结果:        //执行每个任务的线程可能不同。        //线程分配在不同的执行中可能不同。        //这些任务可以按任何顺序执行。        //文档:        // http://msdn.microsoft.com/library/dd783942(VS.100). aspx        static void Main()        {            try            {                Parallel.Invoke(                    BasicAction,// Param #0 - static method                    () =>// Param #1 - lambda expression                    {                        Console.WriteLine("Method=beta, Thread={0}", Thread.CurrentThread.ManagedThreadId);                    },                    delegate()// Param #2 - in-line delegate                    {                        Console.WriteLine("Method=gamma, Thread={0}", Thread.CurrentThread.ManagedThreadId);                    }                );            }//本例中不期望出现异常，但如果仍然从任务中抛出异常，        //它将被包装在AggregateException中，并传播到主线程。            catch (AggregateException e)            {                Console.WriteLine("An action has thrown an exception. THIS WAS UNEXPECTED.\n{0}", e.InnerException.ToString());            }        }        static void BasicAction()        {            Console.WriteLine("Method=alpha, Thread={0}", Thread.CurrentThread.ManagedThreadId);        }    }

注意：所有的并行开发不是简单的以为只要将For换成Parallel.For或调用Parallel.Invoke()执行任务这样简单。