c# Task多线程并行任务中等待所有线程都执行完成

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks;   namespace ConsoleApp {   class Program   {       static void Main(string[] args)     {       var bookShop = new BookShop();       bookShop.Run();     }     }     pulic class Book   {     public int Id { get; set; }       public string Name { get; set; }   }   public class BookShop   {     Random rand = new Random();     Queue<Book> queueBook = new Queue<Book>();     int Max = 10000;     int EachCount = 500;     int Cur = 0;       void LoadData()     {       if (Cur >= Max)       {         //when Cur>=Max,return         Console.WriteLine("Reached max value!");         return;       }       Console.WriteLine("Loading data...");       for (int i = Cur; i < EachCount + Cur; i++)       {         Thread.Sleep(10);         Console.Write(i + " ");         //insert data into Queue<Book>         queueBook.Enqueue(new Book { Id = i, Name = "Name_" + i });       }       Console.WriteLine("");       Cur += EachCount;       Console.WriteLine("Data loaded successful,{0}...", queueBook.Count);     }       public void Run()     {       LoadData();         Console.WriteLine("Tasks have started...");       do       {         Task[] tasks = new Task[10];         for (int i = 0; i < 10; i++)         {           tasks[i] = Task.Factory.StartNew(() => DoSomeWork(1000 * 1));         }         //// Wait for all tasks to complete.         Task.WaitAll(tasks);         //when Queue<Book> is empty,reload data...         LoadData();       } while (queueBook.Count > 0);       //when Cur>=Max,break the while loop       Console.WriteLine("All tasks have completed.");         Console.ReadKey();     }       void DoSomeWork(int val)     {       while (queueBook.Count > 0)       {         var m = queueBook.Dequeue();         Console.WriteLine("DoSomeWork start,i={0},Current thread id:{1}...", m.Id, Thread.CurrentThread.ManagedThreadId);         var sleep = rand.Next(10, 200);         // Pretend to do something.         Thread.Sleep(sleep);         Console.WriteLine("DoSomeWork has completed,sleep:{0},i={1}", sleep, m.Id);       }     }   } }

　　C#多线程中如何等待所有线程的任务都执行完成呢？在.net 4.0以4.0+中，有Task.WaitAll(params Task[] tasks)方法来等待所有Task[],而不需要更多的操作。按照微软官方的文档，我写了一个实例来调试和说明：