Why do I get "CreateFile Failed: 161" when I try to open the serial port?

Question

I get "CreateFile Failed: 161" on the serialPort.Open() line:

. . .
      MessageBox.Show(string.Format("Made it into PrintUtils.PrintBarcode()"));
using (SerialPort serialPort = new SerialPort())
{
    MessageBox.Show("Made it into using statement in PrintUtils.PrintBarcode()"); 
    serialPort.BaudRate = 19200;
    serialPort.Handshake = Handshake.XOnXOff;
    serialPort.DataBits = 8;
    serialPort.Parity = Parity.None;
    serialPort.StopBits = StopBits.One;
    serialPort.PortName = "COM1"; // Is this what it wants?
    MessageBox.Show("Made it beyond the protocol assignments in PrintUtils.PrintBarcode()"); 

    serialPort.Open(); // <-- This causes "CreateFile Failed: 161"
    MessageBox.Show("Opened the serial port in PrintUtils.PrintBarcode()"); 

    Thread.Sleep(2500); // I don't know why this is needed, or if it really is...

    // Try this first:
    serialPort.WriteLine("! 0 200 200 210 1");
    MessageBox.Show("Sent the first line in PrintUtils.PrintBarcode()"); 
    serialPort.WriteLine("TEXT 4 0 30 40 Bonjour la Monde"); //Hola el Mundo --- Hallo die Welt
    MessageBox.Show("Sent the TEXT line in PrintUtils.PrintBarcode()"); 
    serialPort.WriteLine("FORM");
    MessageBox.Show("Sent the FORM line in PrintUtils.PrintBarcode()"); 
    serialPort.WriteLine("PRINT");
    MessageBox.Show("Sent the PRINT line in PrintUtils.PrintBarcode()"); 
    // or (if WriteLine does not include a carriage return and line feed):
    //              serialPort.Write("! 0 200 200 210 1\r\n");
    //              serialPort.Write("TEXT 4 0 30 40 Bonjour la Monde\r\n"); //Hola el Mundo --- Hallo die Welt
    //              serialPort.Write("FORM\r\n");
    //              serialPort.Write("PRINT\r\n");

    serialPort.Close();
    MessageBox.Show("Closed the port in PrintUtils.PrintBarcode()"); 
}

I know that because the last "debug msg" I see is "Made it beyond the protocol assignments in PrintUtils.PrintBarcode()"

Is it because one of the protocols is wrong or in a bad format? Or have I omitted a required protocol assignment?

Answer 1

Error 161 means The specified path is invalid. and you're getting it because your port name is invalid.

Windows CE requires that port names (all driver names actually) be suffixed with a ':' character, so your code should be:

serialPort.PortName = "COM1:";