Is there a C# equivalent to Java's CountDownLatch?

Question

是否有一个C＃等同于Java的CountDownLatch ？

Answer 1

.NET Framework版本4包含新的System.Threading.CountdownEvent类。

Answer 2

Here is a simple implementation (from 9 Reusable Parallel Data Structures and Algorithms ):

To build a countdown latch, you just initialize its counter to n, and have each subservient task atomically decrement it by one when it finishes, for example by surrounding the decrement operation with a lock or with a call to Interlocked.Decrement. Then, instead of a take operation, a thread could decrement and wait for the counter to become zero; when awoken, it will know that n signals have been registered with the latch. Instead of spinning on this condition, as in while (count != 0), it's usually a good idea to let the waiting thread block, in which case you then have to use an event.

 public class CountdownLatch { private int m_remain; private EventWaitHandle m_event; public CountdownLatch(int count) { m_remain = count; m_event = new ManualResetEvent(false); } public void Signal() { // The last thread to signal also sets the event. if (Interlocked.Decrement(ref m_remain) == 0) m_event.Set(); } public void Wait() { m_event.WaitOne(); } }