c# - 连接 USB 设备时出现多个回调

Question

   var watcher = new ManagementEventWatcher();
            var query = new WqlEventQuery("SELECT * FROM Win32_DeviceChangeEvent WHERE EventType = 2 or EventType = 3");
            watcher.EventArrived += new EventArrivedEventHandler(watcher_EventArrived);
            watcher.Query = query;
            watcher.Start();


 private void watcher_EventArrived(object sender, EventArrivedEventArgs e)
        {
            MessageBox.Show("Device Connected or Disconnected");
        }

如果任何插入的设备在 USB 端口中拔出，则此回调有效，但多个回调正在卡明，单次回调要限制什么？有人请帮忙吗？