你如何控制事件在C＃中射击？ [英] How do you control event firing in C#?

问题描述

我写了一个程序，它通过一个网络摄像头提供的图像进行一些处理。有每当从摄像机接收到的新帧触发一个事件。然而，这种情况发生的频率比我想 - 非常频繁，前一个新的事件出现，并再次调用同样的功能我的图像处理功能没有完成。

I wrote a program that does some processing on an image delivered via a web cam. There is an event that fires whenever a new frame is received from the camera. However, this happens more frequently than I'd like - so frequently that my image processing function doesn't complete before a new event appears and calls the same function again.

我如何控制事件触发时？我可以执行我的图像处理，比如，每5事件呢？我相信我有这个伪代码想通了，但我宁愿看到在C＃中的一些例子。

How can I control when the event fires? Can I execute my image processing, say, every 5 events instead? I believe I have the pseudo code figured out, but I would prefer to see some examples in C#.

推荐答案

将事件回调把守，如下所示。然后它不会在同一时间做处理多次

Place the event callback "guarded" as follows. Then it won't be doing the processing many times at the same time.

private bool m_active;
void YourCallback(object sender, EventArgs args) 
{
  if(!m_active) 
  {
    try 
    { 
      m_active = true;
      // Do the work here... 
    }
    finally { m_active = false; }
  }
}

编辑：线程，如果使用f.i.安全信号灯。

private System.Threading.Semaphore m_Semaphore = new System.Threading.Semaphore(0, 1);
void YourCallback(object sender, EventArgs args) 
{
  if(m_Semaphore.WaitOne(0)) 
  {
    try 
    { 
      // Do the work here... 
    }
    finally { m_Semaphore.Release(); }
  }
}

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