C#线程/锁混淆

Question

我有以下代码:

var items = new List<string> {"1", "2", "3"}; // 200 items
foreach(var item in items) {
  ThreadPool.QueueUserWorkItem((DoWork), item);
}

private void DoWork(object obj)
{
  lock(this)
  {
    using(var sw = File.AppendText(@"C:\somepath.txt")
    {
      sw.WriteLine(obj);
    }
  }
}

由于线程，出于某种原因，我得到了写入文件的 200 个项目的随机数。 60 或 127 或有时只有 3。如果我删除 ThreadPool 并只在原始 foreach 循环内写入，则所有 200 项都已成功写入。

不确定为什么会这样？

感谢您的帮助。

Answer 1

以下注释来自 MSDN documentation on ThreadPool说明一切:

The threads in the managed thread pool are background threads. That is, their IsBackground properties are true. This means that a ThreadPool thread will not keep an application running after all foreground threads have exited.

您的应用程序会在您的线程完成运行之前退出(到达 Main 的末尾)。