Finding information about all serial devices connected through USB in C#

My project requires detection of a specific device when it is connected to USB. The only way I can identify this device is by its description/device name, not the com port. What I have found to perform the correct function is using a WMI query and checking the name property:

ManagementObjectSearcher searcher = new ManagementObjectSearcher("Select * from WIN32_SerialPort");
            foreach (ManagementObject port in searcher.Get())
                deviceName = (string)foundPort.GetPropertyValue("Name"); 

I initially tested this by connecting my phone, and the query returned the phone found on COM3 as expected. Then, I connected another device (a USB to serial converter, which more closely resembles the device I need this project for) and the query simply did not find it. It only finds the phone. This device does, however, show up on port COM4 in Device Manager. To spite me even more, the SerialPort class finds both devices, but it does not provide the information I need to identify the device:

    string[] tempPorts = SerialPort.GetPortNames();

I have read numerous threads on SO and elsewhere and cannot find a satisfactory solution. Could someone please clarify why the WIN32_SerialPort query does not find my other device? Is it not considered a win32 serial port for some reason? And, could someone please point me in the direction of a solution to this problem?


How to list all serial ports:

There are several System-Defined Device Setup Classes available to hardware vendors. Properly written drivers for COM-Ports should use the Ports (COM & LPT ports)-class (guid: 4d36e978-e325-11ce-bfc1-08002be10318). Probably this class is used by the device manager as well.

So you can use the following query to list every serial port you also see in the devicemanager:

ManagementObjectSearcher searcher = new ManagementObjectSearcher(
    "SELECT * FROM Win32_PnPEntity WHERE ClassGuid=\"{4d36e978-e325-11ce-bfc1-08002be10318}\""
foreach (ManagementObject queryObj in searcher.Get())
    // do what you like with the Win32_PnpEntity

See this detailed description of the Win32_PnPEntity-class. You should have everything you need for identifying your device.

For determining the port number I examine the name property and extract it. Until now this works fine, but I don't know if the port number is garanteed to be included in the name. I haven't found any serial port device until now, that doesn't have the port number included in the name.

The above query finds every serial port device, no matter if it is a bluetooth SPP, a FTDI-chip, a port on the mainboard, an extension card or a virtual serial port generated by some modem driver (i.e. Globetrotter GTM66xxW).

To determine the type of connection (bluetooth, usb, etc.) you can examine the deviceid (have a look at the first part of the deviceid). There you can also extract the bt-mac address (be careful with that: the deviceid looks different at least on Windows 7 and Windows XP).

Regarding why some devices are not listed with Win32_SerialPort:

I suspect it depends on the driver implementation, since I have some usb-devices that get their ports listed and some that don't.

I think i see what you are trying to do, look at this code made using WMICodeCreator ( link to WMICodeCreator ) from this article

//Below is code pasted from WMICodeCreator
    ManagementObjectSearcher searcher =
        new ManagementObjectSearcher("root\\WMI",
        "SELECT * FROM MSSerial_PortName");

    foreach (ManagementObject queryObj in searcher.Get())
        Console.WriteLine("MSSerial_PortName instance");
        Console.WriteLine("InstanceName: {0}", queryObj["InstanceName"]);

        Console.WriteLine("MSSerial_PortName instance");
        Console.WriteLine("PortName: {0}", queryObj["PortName"]);

        //If the serial port's instance name contains USB 
        //it must be a USB to serial device
        if (queryObj["InstanceName"].ToString().Contains("USB"))
            Console.WriteLine(queryObj["PortName"] + " 
            is a USB to SERIAL adapter/converter");
catch (ManagementException e)
    MessageBox.Show("An error occurred while querying for WMI data: " + e.Message);

Seeing that you want to search by "Name", I think you will need to iterate through all connected devices and query them to get the product name.

Here is code to iterate through WinUSB devices:

  public async Task<IEnumerable<DeviceDefinition>> GetConnectedDeviceDefinitions(uint? vendorId, uint? productId)
        return await Task.Run<IEnumerable<DeviceDefinition>>(() =>
            var deviceDefinitions = new Collection<DeviceDefinition>();
            var spDeviceInterfaceData = new SpDeviceInterfaceData();
            var spDeviceInfoData = new SpDeviceInfoData();
            var spDeviceInterfaceDetailData = new SpDeviceInterfaceDetailData();
            spDeviceInterfaceData.CbSize = (uint)Marshal.SizeOf(spDeviceInterfaceData);
            spDeviceInfoData.CbSize = (uint)Marshal.SizeOf(spDeviceInfoData);

            var guidString = ClassGuid.ToString();
            var copyOfClassGuid = new Guid(guidString);

            var i = APICalls.SetupDiGetClassDevs(ref copyOfClassGuid, IntPtr.Zero, IntPtr.Zero, APICalls.DigcfDeviceinterface | APICalls.DigcfPresent);

            if (IntPtr.Size == 8)
                spDeviceInterfaceDetailData.CbSize = 8;
                spDeviceInterfaceDetailData.CbSize = 4 + Marshal.SystemDefaultCharSize;

            var x = -1;

            while (true)

                var isSuccess = APICalls.SetupDiEnumDeviceInterfaces(i, IntPtr.Zero, ref copyOfClassGuid, (uint)x, ref spDeviceInterfaceData);
                if (!isSuccess)
                    var errorCode = Marshal.GetLastWin32Error();
                    if (errorCode == APICalls.ERROR_NO_MORE_ITEMS)

                    throw new Exception($"Could not enumerate devices. Error code: {errorCode}");

                isSuccess = APICalls.SetupDiGetDeviceInterfaceDetail(i, ref spDeviceInterfaceData, ref spDeviceInterfaceDetailData, 256, out _, ref spDeviceInfoData);
                WindowsDeviceBase.HandleError(isSuccess, "Could not get device interface detail");

                //Note this is a bit nasty but we can filter Vid and Pid this way I think...
                var vendorHex = vendorId?.ToString("X").ToLower().PadLeft(4, '0');
                var productIdHex = productId?.ToString("X").ToLower().PadLeft(4, '0');
                if (vendorId.HasValue && !spDeviceInterfaceDetailData.DevicePath.ToLower().Contains(vendorHex)) continue;
                if (productId.HasValue && !spDeviceInterfaceDetailData.DevicePath.ToLower().Contains(productIdHex)) continue;

                var deviceDefinition = GetDeviceDefinition(spDeviceInterfaceDetailData.DevicePath);



            return deviceDefinitions;

For each of these devices you can query the device like this:

        var isSuccess = WinUsbApiCalls.WinUsb_Initialize(_DeviceHandle, out var defaultInterfaceHandle);
        HandleError(isSuccess, "Couldn't initialize device");

        var bufferLength = (uint)Marshal.SizeOf(typeof(USB_DEVICE_DESCRIPTOR));
        isSuccess = WinUsbApiCalls.WinUsb_GetDescriptor(defaultInterfaceHandle, WinUsbApiCalls.DEFAULT_DESCRIPTOR_TYPE, 0, EnglishLanguageID, out _UsbDeviceDescriptor, bufferLength, out var lengthTransferred);
        HandleError(isSuccess, "Couldn't get device descriptor");

        if (_UsbDeviceDescriptor.iProduct > 0)
            //Get the product name
            var buffer = new byte[256];
            isSuccess = WinUsbApiCalls.WinUsb_GetDescriptor(defaultInterfaceHandle, WinUsbApiCalls.USB_STRING_DESCRIPTOR_TYPE, _UsbDeviceDescriptor.iProduct, 1033, buffer, (uint)buffer.Length, out var transfered);
            HandleError(isSuccess, "Couldn't get product name");

            Product = new string(Encoding.Unicode.GetChars(buffer, 2, (int)transfered));
            Product = Product.Substring(0, Product.Length - 1);

public static partial class WinUsbApiCalls
    public const uint DEVICE_SPEED = 1;
    public const byte USB_ENDPOINT_DIRECTION_MASK = 0X80;
    public const int WritePipeId = 0x80;

    /// <summary>
    /// Not sure where this constant is defined...
    /// </summary>
    public const int DEFAULT_DESCRIPTOR_TYPE = 0x01;
    public const int USB_STRING_DESCRIPTOR_TYPE = 0x03;

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_ControlTransfer(IntPtr InterfaceHandle, WINUSB_SETUP_PACKET SetupPacket, byte[] Buffer, uint BufferLength, ref uint LengthTransferred, IntPtr Overlapped);

    [DllImport("winusb.dll", SetLastError = true, CharSet = CharSet.Auto)]
    public static extern bool WinUsb_GetAssociatedInterface(SafeFileHandle InterfaceHandle, byte AssociatedInterfaceIndex, out SafeFileHandle AssociatedInterfaceHandle);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_GetDescriptor(SafeFileHandle InterfaceHandle, byte DescriptorType, byte Index, ushort LanguageID, out USB_DEVICE_DESCRIPTOR deviceDesc, uint BufferLength, out uint LengthTransfered);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_GetDescriptor(SafeFileHandle InterfaceHandle, byte DescriptorType, byte Index, UInt16 LanguageID, byte[] Buffer, UInt32 BufferLength, out UInt32 LengthTransfered);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_Free(SafeFileHandle InterfaceHandle);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_Initialize(SafeFileHandle DeviceHandle, out SafeFileHandle InterfaceHandle);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_QueryDeviceInformation(IntPtr InterfaceHandle, uint InformationType, ref uint BufferLength, ref byte Buffer);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_QueryInterfaceSettings(SafeFileHandle InterfaceHandle, byte AlternateInterfaceNumber, out USB_INTERFACE_DESCRIPTOR UsbAltInterfaceDescriptor);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_QueryPipe(SafeFileHandle InterfaceHandle, byte AlternateInterfaceNumber, byte PipeIndex, out WINUSB_PIPE_INFORMATION PipeInformation);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_ReadPipe(SafeFileHandle InterfaceHandle, byte PipeID, byte[] Buffer, uint BufferLength, out uint LengthTransferred, IntPtr Overlapped);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_SetPipePolicy(IntPtr InterfaceHandle, byte PipeID, uint PolicyType, uint ValueLength, ref uint Value);

    [DllImport("winusb.dll", SetLastError = true)]
    public static extern bool WinUsb_WritePipe(SafeFileHandle InterfaceHandle, byte PipeID, byte[] Buffer, uint BufferLength, out uint LengthTransferred, IntPtr Overlapped);

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