private void serialBarcode_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {
            try
            {
                var line = serialBarcode.ReadTo("\r");
                BeginInvoke(new LineReceivedEvent(LineReceived), line);
                this.serialBarcode.DiscardInBuffer();
            }
            catch
            {}
        }