1     class Program
  2     {
  3         //構造大象和冰箱
  4         private static ElephantsAndFridges elephantsAndFridges = new ElephantsAndFridges();
  5 
  6         static void Main(string[] args)
  7         {
  8             int taskCnt = 3;
  9 
 10             //此處有3個Task來完成工作（註意多任務與多線程及堆棧數據邊界）
 11
 
             //並將每個任務的執行結果返回
 12             Task<PhaseTask>[] tasks = new Task<PhaseTask>[taskCnt];
 13 
 14             //使多個任務能夠采用並行方式依據某種算法在多個階段中協同工作
 15             // 參數:
 16             //   participantCount:
 17             //     參與線程的數量。
 18             //
 19             //   postPhaseAction:
 
 20             //     每個階段完成之後執行。 可傳遞 null ，以指示不執行任何操作
 21             Barrier barrier = new Barrier(taskCnt, (b) =>
 22                 {
 23                     Console.WriteLine(string.Format("第{0}階段已完成", b.CurrentPhaseNumber + 1));
 24                     Console.WriteLine();
 25                 });
 
 26             for (int i = 0; i < taskCnt; i++)
 27             {
 28                 //使用Task工廠啟3個任務
 29                 tasks[i] = Task<PhaseTask>.Factory.StartNew((obj) =>
 30                 {
 31                     int cnt = (int)obj;
 32 
 33                     //一個任務一個冰箱（冰箱具有打開和關閉冰箱門及放大象操作）
 34                     Fridge fridge = new Fridge();
 35 
 36                     //註：此處不能用i，存在執行順序問題
 37                     //例如：還未開始從elephantsAndFridges中拿數據，i的值就已經加1了，此時拿的就是i+1位置，而非i位置的數據
 38                     fridge.ElephantName = elephantsAndFridges.elephants.ElementAtOrDefault(cnt).ElephantName;
 39                     fridge.FridgeName = elephantsAndFridges.fridges.ElementAtOrDefault(cnt).FridgeName;
 40 
 41                     //第一步
 42                     fridge.PhaseTaskResult.FirstResult = fridge.OpenTheDoor();
 43                     //用信號通知的參與者已達到屏障和所有其他參與者到達屏障也會等待
 44                     barrier.SignalAndWait();
 45 
 46                     //第二部
 47                     fridge.PhaseTaskResult.SecondResult = fridge.EnterTheFridge();
 48                     barrier.SignalAndWait();
 49 
 50                     //第三部
 51                     fridge.PhaseTaskResult.ThirdResult = fridge.CloseTheDoor();
 52                     barrier.SignalAndWait();
 53 
 54                     //返回每個步驟得到的結果
 55                     return fridge.PhaseTaskResult;
 56 
 57                 }, i);
 58             }
 59 
 60             //最後ContinueWhenAll，輸出每個任務記錄的結果，釋放Barrier
 61             var continueTask = Task.Factory.ContinueWhenAll(tasks, (t) =>
 62             {
 63                 foreach (var item in t)
 64                 {
 65                     Console.Write(string.Format("任務{0}：", t.ToList().IndexOf(item) + 1));
 66                     Console.WriteLine(item.Result.FirstResult);
 67                     Console.Write(string.Format("任務{0}：", t.ToList().IndexOf(item) + 1));
 68                     Console.WriteLine(item.Result.SecondResult);
 69                     Console.Write(string.Format("任務{0}：", t.ToList().IndexOf(item) + 1));
 70                     Console.WriteLine(item.Result.ThirdResult);
 71                 }
 72                 Console.WriteLine();
 73                 Console.WriteLine("已將全部大象放入全部冰箱");
 74                 barrier.Dispose();
 75             });
 76 
 77             Console.ReadLine();
 78         }
 79     }
 80 
 81     /// <summary>
 82     /// 大象
 83     /// </summary>
 84     public class Elephant
 85     {
 86         public String ElephantName { get; set; }
 87     }
 88 
 89     /// <summary>
 90     /// 冰箱
 91     /// </summary>
 92     public class Fridge
 93     {
 94         public String FridgeName { get; set; }
 95 
 96         public String ElephantName { get; set; }
 97 
 98         public PhaseTask PhaseTaskResult = new PhaseTask();
 99 
100         public String OpenTheDoor()
101         {
102             return PhaseTaskResult.FirstResult = PhaseTaskResult.PhaseFirst(ElephantName, FridgeName);
103         }
104 
105         public String EnterTheFridge()
106         {
107             return PhaseTaskResult.SecondResult = PhaseTaskResult.PhaseSecond(ElephantName, FridgeName);
108         }
109 
110         public String CloseTheDoor()
111         {
112             return PhaseTaskResult.ThirdResult = PhaseTaskResult.PhaseThird(ElephantName, FridgeName);
113         }
114     }
115 
116     /// <summary>
117     /// 構造大象和冰箱
118     /// </summary>
119     public class ElephantsAndFridges
120     {
121         public List<Elephant> elephants;
122 
123         public List<Fridge> fridges;
124 
125         public ElephantsAndFridges()
126         {
127             elephants = new List<Elephant>()
128             {
129                 new Elephant() {ElephantName="大象甲" },
130                 new Elephant() {ElephantName="大象乙" },
131                 new Elephant() {ElephantName="大象丙" }
132             };
133 
134             fridges = new List<Fridge>()
135             {
136                 new Fridge(){ FridgeName="冰箱甲"},
137                 new Fridge(){ FridgeName="冰箱乙"},
138                 new Fridge(){ FridgeName="冰箱丙"}
139             };
140         }
141     }
142 
143     /// <summary>
144     /// 把大象放入冰箱，共需3步
145     /// 第一步，打開冰箱門
146     /// 第二部，把大象放進冰箱
147     /// 第三部，關閉冰箱門
148     /// 該類提供三個步驟和每個步驟得到的結果
149     /// </summary>
150     public class PhaseTask
151     {
152         public String FirstResult { get; set; }
153 
154         public String SecondResult { get; set; }
155 
156         public String ThirdResult { get; set; }
157 
158         public String PhaseFirst(string elephantName, string fridgeName)
159         {
160             string str = string.Format("第一步：為{0}打開{1}門", elephantName, fridgeName);
161             Console.WriteLine(str);
162             return FirstResult = str;
163         }
164 
165         public String PhaseSecond(string elephantName, string fridgeName)
166         {
167             string str = string.Format("第二步：把{0}放入{1}", elephantName, fridgeName);
168             Console.WriteLine(str);
169             return SecondResult = str;
170         }
171 
172         public String PhaseThird(string elephantName, string fridgeName)
173         {
174             string str = string.Format("第三步：為{0}關閉{1}門", elephantName, fridgeName);
175             Console.WriteLine(str);
176             return ThirdResult = str;
177         }
178     }

使用Barrier分三步將大象放入冰箱