public string ReadRfidCard(byte COMPort=0)
        {
            if (COMPort == 0) COMPort = 0x05;

            string Uid="";
            string CType="";

            try
            {
                RFIDAPI rfidApi = new RFIDAPI();
                rfidApi.RFID_OpenReader(COMPort);
                rfidApi.RFID_OpenCard(out Uid, out CType);
                rfidApi.RFID_CloseCard();
                rfidApi.RFID_CloseReader(0x05);
            }
            catch(Exception ex)
            {
                Uid = "error";
            }
            if (String.IsNullOrWhiteSpace(Uid)) Uid = "none";
            if (String.IsNullOrWhiteSpace(CType)) CType = "none";

            return Uid;
        }