如何提高C＃事件？ [英] How do I wait for a C# event to be raised?

问题描述

我有一个发件人类，发送消息在 IChannel ：

public class MessageEventArgs : EventArgs {
  public Message Message { get; private set; }
  public MessageEventArgs(Message m) { Message = m; }
}

public interface IChannel {
  public event EventHandler<MessageEventArgs> MessageReceived;
  void Send(Message m);
}

public class Sender {
  public const int MaxWaitInMs = 5000;
  private IChannel _c = ...;

  public Message Send(Message m) {
    _c.Send(m);
    // wait for MaxWaitInMs to get an event from _c.MessageReceived
    // return the message or null if no message was received in response
  }
}

当我们发送消息时， ICHannel 有时会根据通过提高 MessageReceived 事件发送了什么样的消息。事件参数包含感兴趣的消息。

When we send messages, the IChannel sometimes gives a response depending on what kind of Message was sent by raising the MessageReceived event. The event arguments contain the message of interest.

我想要 Sender.Send（）方法等待一个短时间来看看这个事件是否提高。如果是这样，我将返回其 MessageEventArgs.Message 属性。如果没有，我返回一个null 消息。

I want Sender.Send() method to wait for a short time to see if this event is raised. If so, I'll return its MessageEventArgs.Message property. If not, I return a null Message.

我怎么能这样等待？我不喜欢用 ManualResetEvents 做线程工作，所以坚持定期的事件将是

How can I wait in this way? I'd prefer not to have do the threading legwork with ManualResetEvents and such, so sticking to regular events would be optimal for me.

推荐答案

使用 AutoResetEvent 。

Gimme几分钟，我会一起捡样本。

Gimme a few minutes and I'll throw together a sample.

这是：

public class Sender
{
    public static readonly TimeSpan MaxWait = TimeSpan.FromMilliseconds(5000);

    private IChannel _c;
    private AutoResetEvent _messageReceived;

    public Sender()
    {
        // initialize _c
        this._messageReceived = new AutoResetEvent(false);
        this._c.MessageReceived += this.MessageReceived;
    }

    public Message Send(Message m)
    {
        this._c.Send(m);
        // wait for MaxWaitInMs to get an event from _c.MessageReceived
        // return the message or null if no message was received in response


        // This will wait for up to 5000 ms, then throw an exception.
        this._messageReceived.WaitOne(MaxWait);

        return null;
    }

    public void MessageReceived(object sender, MessageEventArgs e)
    {
        //Do whatever you need to do with the message

        this._messageReceived.Set();
    }
}

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