c＃中返回值的多線程問題

Question

我想我正在做一些令人難以置信的錯誤，但我不知道是什麼。當我運行這段代碼時，兩個線程（thread1和thread2）立即無法生效，但val1和val2中的值沒有正確設置。

不在線程中的代碼部分工作，如果我調用級別= 0的進程，我會在val1和val2中得到兩個正確的結果。

public int Process(int left, int right, List<int> array, int level) 
    { 

     int val1, val2; 
     val1 = 0; 
     val2 = 0; 

     int val = array[left] + array[right] + (right - left); 

     if (level > 0) 
     { 
      if ((right - left) > 1) 
      { 
       var thread1 = new Thread(() => { val1 = Process(left, right - 1, array, level - 1); }); 

       var thread2 = new Thread(() => { val2 = Process(left - 1, right, array, level - 1); }); 

       while (thread1.IsAlive) 
       { 
        System.Threading.Thread.Sleep(100); 
       } 

       while (thread2.IsAlive) 
       { 
        System.Threading.Thread.Sleep(100); 
       } 

       val = Math.Max(Math.Max(val1, val2), val); 
      } 
     } 
     else 
     { 

      if ((right - left) > 1) 
      { 
       val1 = Process(left, right - 1, array, level); 
       val2 = Process(left + 1, right, array, level); 
       val = Math.Max(Math.Max(val1, val2), val); 
      } 
     } 

     return val; 
    } 

Answer 1

您創建了線程，但未啓動它們。創建後調用Thread.Start（）。

var thread1 = new Thread(() => { val1 = Process(left, right - 1, array, level - 1); }); 
var thread2 = new Thread(() => { val2 = Process(left - 1, right, array, level - 1); }); 
thread1.Start(); 
thread2.Start();