List of SerialPorts queried using WMI differs from devicemanager?

Question

I have the following serial ports listed in my devicemanager:

• COM3
• COM4 (BT)
• COM5 (BT)
• COM6 (GlobeTrotter MO67xx - Control Interface

Answer 1

The Win32_SerialPort class used in this article reports the physical com ports, if you wanna enumerate all the serial ports including the USB-Serial/COM ports, you must use the MSSerial_PortName class located in the root\wmi namespace.

Also try these classes located in the same namespace

• MSSerial_CommInfo
• MSSerial_CommProperties
• MSSerial_HardwareConfiguration
• MSSerial_PerformanceInformation

Note : If you want to know the properties and methods of this class you can use the WMI Delphi Code Creator.

Answer 2

I had a similar issues trying to have an application locate the COM port for a USB Serial device.

By using the scope \\localhost\root\CIMV2 for the query SELECT * FROM Win32_PnPEntity WHERE ConfigManagerErrorCode = 0, the application was able to find COM ports via each returned object's caption or locate the exact port by checking the caption for the device name.

ManagementObjectSearcher comPortSearcher = new ManagementObjectSearcher(@"\\localhost\root\CIMV2", "SELECT * FROM Win32_PnPEntity WHERE ConfigManagerErrorCode = 0");

        using (comPortSearcher)
        {
            string caption = null;
            foreach (ManagementObject obj in comPortSearcher.Get())
            {
                if (obj != null)
                {
                    object captionObj = obj["Caption"];
                    if (captionObj != null)
                    {
                        caption = captionObj.ToString();
                            if (caption.Contains("CH340"))
                            {
                                _currentSerialSettings.PortName = caption.Substring(caption.LastIndexOf("(COM")).Replace("(", string.Empty).Replace(")", string.Empty);
                            }
                    }
                }
            }
        }

The parsing code was found at [C#] How to programmatically find a COM port by friendly name

Answer 3

In my case, I have physical serial ports, USB serial ports, and com0com virtual serial ports. I need both the full names, and COM port addresses.

The query suggested in this answer does not find com0com ports. The query suggested in this answer requires Administrator priviledges.

SELECT * FROM Win32_PnPEntity find all devices. It returns physical devices like this, and address can be parsed from Caption:

Serial Port for Barcode Scanner (COM13)

However, for com0com ports Caption is like this (no address):

com0com - serial port emulator

SELECT * FROM Win32_SerialPort returns addresses (DeviceID), as well as full names (Name). However, it only finds physical serial ports and com0com ports, not USB serial ports.

So in the end, I need two WMI calls: SELECT * FROM Win32_SerialPort (address is DeviceID) and SELECT * FROM Win32_PnPEntity WHERE Name LIKE '%(COM%' (address can be parsed from Caption). I have narrowed down the Win32_PnPEntity call, because it only needs to find devices that were not found in the first call.

Answer 4

I found the solution.

The following query (root\CIMV2) gets the requested results:

SELECT * FROM Win32_PnPEntity WHERE ClassGuid="{4d36e978-e325-11ce-bfc1-08002be10318}"

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Update

This answer is pretty old now. Ehen I asked it I still had to consider WinXP and was using Windows7. Since I don't deal with serial ports any more, I can't give any new information on that issue. At that time this solution reported all ports that the devicemanager was showing. But I know listing serial ports is not that easy so this answer might not be correct in all scenarios.