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

TK. picture TK. · Oct 12, 2008 · Viewed 87.3k times · Source

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
}
catch (Exception ex)
{
    // handle the exception
}

However, I would like to programatically check so I can attempt to use another COM port or some such.

Answer

Fionn picture Fionn · Oct 12, 2008

I needed something similar some time ago, to search for a device.

I obtained a list of available COM ports and then simply iterated over them, if it didn't throw an exception i tried to communicate with the device. A bit rough but working.

var portNames = SerialPort.GetPortNames();

foreach(var port in portNames) {
    //Try for every portName and break on the first working
}