C# TPL学习

程序Ⅰ：通过Task类创建新线程

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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks;   namespace Test000 {     class Program     {         /// <summary>         /// Task类封装         /// </summary>         class MyTask         {             /// <summary>             /// 第一个Task类，每秒计数，计数5次             /// </summary>             public static void T1()             {                 Console.WriteLine("Task #{0}: Begin!", Task.CurrentId);                 for (int i = 0; i < 5; i++)                 {                     Thread.Sleep(1000);                     Console.WriteLine("Task #{0}: {1}", Task.CurrentId, i);                 }                 Console.WriteLine("Task #{0}: Terminated!", Task.CurrentId);             }               /// <summary>             /// 第二个Task类，每秒计数，计数5次             /// </summary>             public static void T2()             {                 Console.WriteLine("Task #{0}: Begin!", Task.CurrentId);                 Thread.Sleep(500);                 for (int i = 0; i < 5; i++)                 {                     Thread.Sleep(1000);                     Console.WriteLine("Task #{0}: {1}", Task.CurrentId, i);                 }                 Console.WriteLine("Task #{0}: Terminated!", Task.CurrentId);             }         }           static void Main(string[] args)         {             //建立两个Task             Task tsk1 = new Task(MyTask.T1);             Console.WriteLine("Task #{0}: Constructed!", tsk1.Id);             Task tsk2 = new Task(MyTask.T2);             Console.WriteLine("Task #{0}: Constructed!", tsk1.Id);               //运行Task             tsk1.Start();             tsk2.Start();               //等待Task运行结束             WaitAll(tsk1, tsk2);               Console.ReadLine();         }           /// <summary>         /// 等待所有的Task运行结束         /// </summary>         /// <param name="tsks">等待的Task类</param>         public static void WaitAll(params Task[] tsks)         {             foreach (var t in tsks)             {                 t.Wait();             }         }     } }

运行结果

程序Ⅱ：通过TaskFactory启动任务并接收任务的返回值

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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Test001 {     class Program     {         /// <summary>         /// Task类封装         /// </summary>         class MyTask         {             /// <summary>             /// 求1+2+...+n的和             /// </summary>             /// <param name="n">数n</param>             /// <returns></returns>             public static int Sum(object n)             {                 int x = (int)n;                 int sum = 0;                 for (int i = 1; i <= x; i++)                 {                     sum += i;                 }                 return sum;             }         }           static void Main(string[] args)         {             Task<int> tsk = Task<int>.Factory.StartNew(MyTask.Sum, 100);             Console.WriteLine("Result is: " + tsk.Result);               Console.ReadLine();         }     } }

运行结果

程序Ⅲ：通过Parallel类的Invoke函数，并行调用多个Task

本程序中通过Lambda表达式来建立新的Task

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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks;   namespace Test002 {     class Program     {         static void Main(string[] args)         {             Parallel.Invoke                 (                     () =>                     {                         Console.WriteLine("Task #{0}: Begin!", Task.CurrentId);                         for (int i = 0; i < 5; i++)                         {                             Thread.Sleep(1000);                             Console.WriteLine("Task #{0}: {1}", Task.CurrentId, i);                         }                         Console.WriteLine("Task #{0}: Terminated!", Task.CurrentId);                     },                     () =>                     {                         Console.WriteLine("Task #{0}: Begin!", Task.CurrentId);                         Thread.Sleep(500);                         for (int i = 0; i < 5; i++)                         {                             Thread.Sleep(1000);                             Console.WriteLine("Task #{0}: {1}", Task.CurrentId, i);                         }                         Console.WriteLine("Task #{0}: Terminated!", Task.CurrentId);                     }                 );               Console.ReadLine();         }     } }

运行结果

程序Ⅳ：通过Parallel类的For和FoeEach函数，并行调用多个Task

本程序中，通过Stopwatch类统计程序段的运行时间

从例中可以看出：不是所有的循环在并行化时都是有效的。通常，对于小型循环或执行非常简单的操作的循环来说，使用顺序循环比并行循环更加快速

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using System; using System.Collections.Generic; using System.Diagnostics; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace Test003 {     class Program     {         /// <summary>         /// 示例函数         /// </summary>         /// <param name="n">参数</param>         public static void DoSomeThing(int n)         {             int sum = 0;             for (int i = 0; i < n * 100; i++)             {                 sum += i;             }         }           static void Main(string[] args)         {             //计时工具，需要System.Diagnostics             Stopwatch sw = new Stopwatch();               //统计依次顺序调用函数的时间             sw.Start();             for (int i = 100; i < 105; i++)             {                 DoSomeThing(100);             }             sw.Stop();             Console.WriteLine("TotalTime: {0}", sw.Elapsed.TotalMilliseconds);             sw.Reset();               Console.WriteLine("===========");               //统计并行调用函数的时间             sw.Start();             Parallel.For(100, 105, DoSomeThing);             sw.Stop();             Console.WriteLine("TotalTime: {0}", sw.Elapsed.TotalMilliseconds);             sw.Reset();               Console.WriteLine("===========");               //统计并行调用函数的时间             sw.Start();             Parallel.ForEach(new int[5] { 100, 101, 102, 103, 104 }, DoSomeThing);             sw.Stop();             Console.WriteLine("TotalTime: {0}", sw.Elapsed.TotalMilliseconds);               sw.Reset();             Console.ReadLine();         }     } }

运行结果

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