rfidreader_hardreader.cs

static void SerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    Console.WriteLine($"Serial recebido");
    string RxString = _serialPort.ReadExisting();
    string SerialID;

    if (RxString.IndexOf("\r\n") > -1 || RxString.IndexOf("|") > -1)
    {
        SerialID = RxString.Replace("\r\n", "").Replace("|", "");
        Console.WriteLine($"Serial: {SerialID}");
    }
}