Multiple callback came while Usb device connected

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");
        }

if any device plugged on unplugged in usb port this call back works, but multiple callbacks are cumming, what to to restrict with single call back ? any one please help ?