线程如何与彼此通信？

Question

线程如何与彼此通信？他们不使用彼此的价值观,那么他们之间的沟通方式是什么？

Answer 1

线程可以通过几种方式相互通信.此列表并非详尽无遗,但确实包含了最常用的策略.

• 共享内存,如变量或其他一些数据结构
• 同步原语,如锁和sempahores
• 事件,如ManualResetEvent或AutoResetEvent

共享内存

public static void Main()
{
  string text = "Hello World";
  var thread = new Thread(
    () =>
    {
      Console.WriteLine(text); // variable read by worker thread
    });
  thread.Start();
  Console.WriteLine(text); // variable read by main thread
}

同步原语

public static void Main()
{
  var lockObj = new Object();
  int x = 0;
  var thread = new Thread(
    () =>
    {
      while (true)
      {
        lock (lockObj) // blocks until main thread releases the lock
        {
          x++;
        }
      }
    });
  thread.Start();
  while (true)
  {
    lock (lockObj) // blocks until worker thread releases the lock
    {
      x++;
      Console.WriteLine(x);
    }
  }
}

活动

public static void Main()
{
  var are = new AutoResetEvent(false);
  var thread = new Thread(
    () =>
    {
      while (true)
      {
        Thread.Sleep(1000);
        are.Set(); // worker thread signals the event
      }
    });
  thread.Start();
  while (are.WaitOne()) // main thread waits for the event to be signaled
  {
    Console.WriteLine(DateTime.Now);
  }
}

Answer 2

线程可以共享值，但这样做时必须小心。在.Net 中，最常见的方法是lock语句和Interlocked 类。