程序无端挂起

Question

我正在使用tpl并行执行数据。的问题是，有时它挂起无故给予这样的输出：

The thread '<No Name>' (0x4aa4) has exited with code 0 (0x0). 
The thread '<No Name>' (0x2bf4) has exited with code 0 (0x0). 
The thread '<No Name>' (0x417c) has exited with code 0 (0x0). 
The thread '<No Name>' (0x432c) has exited with code 0 (0x0). 
The thread '<No Name>' (0x3ad0) has exited with code 0 (0x0). 
The thread '<No Name>' (0x4440) has exited with code 0 (0x0). 
The thread '<No Name>' (0x24e8) has exited with code 0 (0x0). 
The thread '<No Name>' (0x3354) has exited with code 0 (0x0). 
The thread '<No Name>' (0x4a30) has exited with code 0 (0x0). 

该程序将仍然被执行，当我暂停在Visual Studio中它会暂停，其中i具有平行过程对foreach：

Parallel.ForEach 
(
    hold1.remainingHolds.ToArray(), 
    subSequence => 
    { 
     //only if subsequence has 1 common substring 
     if (checkIfCommon(remainingSequence, subSequence.ToString()) == 1) 
     { 
     goDownLinkType2(subSequence.ToString().Split(','), 0, 
      (SuffixNode)hold1.childHolds[subSequence.ToString().Split(',')[0]]); 
     } 
    } 
); 

我不认为它是一个死锁的原因有没有情况下可以有一个线程在等待不同的资源和evetually锁定对方

应该这个方法里面输入和recursivley去道琼斯指数后缀树，直到它会等待直到没有线程向阵列列表添加任何对象

Boolean flag = false; 
public void goDownLinkType2 
     (string[] splittedString, 
     int index, SuffixNode currentNode) 
     { 
      Boolean writingFlag = false; 
      if (index == 2) 
      { 
      while(writingFlag == false) 
      { 
       while(flag == true) 
       { 
     //blocked 
       } 
       if (flag == false) 
       { 
        flag = true; 
       if(!secondChoiceResults.Contains 
        (currentNode.representingStance.SequenceOfHolds)) 
       { 
        Console.WriteLine("new addition"); 
        secondChoiceResults.Add 
         (currentNode.representingStance.SequenceOfHolds, 
         currentNode.representingStance); 
        } 
        flag = false; 
        writingFlag = true; 
       } 
      } 

     } 
     else 
     { 
      int nextIndex = index + 1; 
      goDownLinkType2 
       (splittedString, 
       nextIndex, 
       (SuffixNode)currentNode.childHolds[splittedString[nextIndex]] 
      ); 
      } 
     } 

Answer 1

抛弃“标志”变量并使用锁定语句。在这段代码中，可能有多个线程处于关键部分（即一个线程将设置flag = true，而另一个线程将flag == false评估为true（未来只使用！标志）

lock(obj) 
{ 
    // critical section here 
} 

OBJ只是需要向所有线程访问的对象的引用

这里是我的修改代码：

public void goDownLinkType2(string[] splittedString, int index, SuffixNode currentNode) 
{ 
    Boolean writingFlag = false; 
    if (index == 2) 
    { 
     while(writingFlag == false) 
     { 
      lock(this) 
      //while(flag == true) 
      //{ 
       //blocked 
      //} 
      //if (flag == false) 
      { 
       //flag = true; 
       if (!secondChoiceResults.Contains(currentNode.representingStance.SequenceOfHolds)) 
       { 
        Console.WriteLine("new addition"); 
        secondChoiceResults.Add(currentNode.representingStance.SequenceOfHolds, currentNode.representingStance); 
       } 
       //flag = false; 
       writingFlag = true; 
      } 
     } 


    } 
    else 
    { 
     int nextIndex = index + 1; 
     goDownLinkType2(splittedString, nextIndex, (SuffixNode)currentNode.childHolds[splittedString[nextIndex]]); 
    } 
}