当事件被引发一次时，c# 事件处理程序被多次调用

Question

下面是我的代码，第一部分是我引发事件的地方，第二部分是我在另一个类中使用它的地方。看起来很简单，但日志显示即使事件被引发一次，事件也会在使用此事件的类上触发 20 多次。有什么想法吗？

IBSerialPort 类:

public delegate void PacketReceivedHandler(object sender, PacketReceivedEventArgs e);
public event PacketReceivedHandler OnPacketReceived;

public class PacketReceivedEventArgs : EventArgs
{
  public Packet PacketReceived { get; private set; }

  public PacketReceivedEventArgs(Packet packet)
  {
    PacketReceived = packet;
  }
}

// raise event
if (OnPacketReceived != null)
{
    Log("This is only called ONCE!");
    PacketReceivedEventArgs args = new PacketReceivedEventArgs(data);
    OnPacketReceived(this, args);
}

使用 IBSerialPort 并使用其 OnPacketReceived 事件的类:

IBSerialPort ibSerialPort = null;
..
if (ibSerialPort == null)
{
  Log("This is only called once");

  ibSerialPort = IBSerialPort.Instance;

  ibSerialPort.OnPacketReceived += ibSerialPort_OnPacketReceived;
}

void ibSerialPort_OnPacketReceived(object sender, IBSerialPort.PacketReceivedEventArgs args)
{
   Log("This is called ~25 times!!!!");
}

Answer 1

试试这个，这将注销任何上一个订阅者:

ibSerialPort.OnPacketReceived -= ibSerialPort_OnPacketReceived;   // unregister
ibSerialPort.OnPacketReceived += ibSerialPort_OnPacketReceived;  //register