C# check if a COM (Serial) port is already open

Question

Is there an easy way of programmatically checking if a serial COM port is already open/being used?

Normally I would use:

try
{
    // open port
}
cat         


        

Answer 1

Sharing what worked for me (a simple helper method):

private string portName { get; set; } = string.Empty;

    /// 

    /// Returns SerialPort Port State (Open / Closed)
    /// 
    /// 
    internal bool HasOpenPort()
    {
        bool portState = false;

        if (portName != string.Empty)
        {
            using (SerialPort serialPort = new SerialPort(portName))
            {
                foreach (var itm in SerialPort.GetPortNames())
                {
                    if (itm.Contains(serialPort.PortName))
                    {
                        if (serialPort.IsOpen) { portState = true; }
                        else { portState = false; }
                    }
                }
            }
        }

        else { System.Windows.Forms.MessageBox.Show("Error: No Port Specified."); }

        return portState;
}

Notes:
- For more advanced technique(s) I recommend using ManagementObjectSearcher Class.
More info Here.
- For Arduino devices I would leave the Port Open.
- Recommend using a Try Catch block if you need to catch exceptions.
- Check also: "TimeoutException"
- More information on how to get SerialPort (Open) Exceptions Here.