Find USB drive letter from VID/PID (Needed for XP and higher)

Question

So I thought I would include the final answer here so you don\'t have to make sense of this post. Big thanks to Simon Mourier for taking the time to figure this one out.

Answer 1

I've had the same problem and also browsing through the WMI did not help me out, really.

But I ended up with these few lines of code, and it works great for me:

private string GetAvailableStorageDrive()
{
    foreach (var info in System.IO.DriveInfo.GetDrives())
    {
        if (info.DriveType == System.IO.DriveType.Removable && 
             info.IsReady && 
            !info.Name.Equals("A:\\"))
        {
            return info.Name;
        }
    }
    return string.Empty;
}

Basically the above function looks if the DriveType is Removable andalso if the Drive is ready. I also exclude the drive letter 'A' because in default windows environments, this is the Floppy.

Description of DriveType.Removable:

The drive is a removable storage device, such as a floppy disk drive or a USB flash drive.

Note: As CodeCaster pointed out, this function will also return removable storage devices such as SATA. So if that's the case, you will have to look into more complex solutions as provided by others.

Answer 2

I may be mistaken but it seems WMI doesn't know about the parent-child relation that exists in the Windows device setup API.

So, I have created a small Device utility class that can add this missing link from the native Setup API. Here is how you would use it in your original USBDeviceInfo class:

class USBDeviceInfo
{
    public USBDeviceInfo(string deviceID, string pnpDeviceID, string description)
    {
        this.DeviceID = deviceID;
        this.PnpDeviceID = pnpDeviceID;
        this.Description = description;
    }

    public string DeviceID { get; private set; }
    public string PnpDeviceID { get; private set; }
    public string Description { get; private set; }

    public IEnumerable<string> GetDiskNames()
    {
        using (Device device = Device.Get(PnpDeviceID))
        {
            // get children devices
            foreach (string childDeviceId in device.ChildrenPnpDeviceIds)
            {
                // get the drive object that correspond to this id (escape the id)
                foreach (ManagementObject drive in new ManagementObjectSearcher("SELECT DeviceID FROM Win32_DiskDrive WHERE PNPDeviceID='" + childDeviceId.Replace(@"\", @"\\") + "'").Get())
                {
                    // associate physical disks with partitions
                    foreach (ManagementObject partition in new ManagementObjectSearcher("ASSOCIATORS OF {Win32_DiskDrive.DeviceID='" + drive["DeviceID"] + "'} WHERE AssocClass=Win32_DiskDriveToDiskPartition").Get())
                    {
                        // associate partitions with logical disks (drive letter volumes)
                        foreach (ManagementObject disk in new ManagementObjectSearcher("ASSOCIATORS OF {Win32_DiskPartition.DeviceID='" + partition["DeviceID"] + "'} WHERE AssocClass=Win32_LogicalDiskToPartition").Get())
                        {
                            yield return (string)disk["DeviceID"];
                        }
                    }
                }
            }
        }
    }
}

And here is the new Device class:

public sealed class Device : IDisposable
{
    private IntPtr _hDevInfo;
    private SP_DEVINFO_DATA _data;

    private Device(IntPtr hDevInfo, SP_DEVINFO_DATA data)
    {
        _hDevInfo = hDevInfo;
        _data = data;
    }

    public static Device Get(string pnpDeviceId)
    {
        if (pnpDeviceId == null)
            throw new ArgumentNullException("pnpDeviceId");

        IntPtr hDevInfo = SetupDiGetClassDevs(IntPtr.Zero, pnpDeviceId, IntPtr.Zero, DIGCF.DIGCF_ALLCLASSES | DIGCF.DIGCF_DEVICEINTERFACE);
        if (hDevInfo == (IntPtr)INVALID_HANDLE_VALUE)
            throw new Win32Exception(Marshal.GetLastWin32Error());

        SP_DEVINFO_DATA data = new SP_DEVINFO_DATA();
        data.cbSize = Marshal.SizeOf(data);
        if (!SetupDiEnumDeviceInfo(hDevInfo, 0, ref data))
        {
            int err = Marshal.GetLastWin32Error();
            if (err == ERROR_NO_MORE_ITEMS)
                return null;

            throw new Win32Exception(err);
        }

        return new Device(hDevInfo, data) {PnpDeviceId = pnpDeviceId};
    }

    public void Dispose()
    {
        if (_hDevInfo != IntPtr.Zero)
        {
            SetupDiDestroyDeviceInfoList(_hDevInfo);
            _hDevInfo = IntPtr.Zero;
        }
    }

    public string PnpDeviceId { get; private set; }

    public string ParentPnpDeviceId
    {
        get
        {
            if (IsVistaOrHiger)
                return GetStringProperty(DEVPROPKEY.DEVPKEY_Device_Parent);

            uint parent;
            int cr = CM_Get_Parent(out parent, _data.DevInst, 0);
            if (cr != 0)
                throw new Exception("CM Error:" + cr);

            return GetDeviceId(parent);
        }
    }

    private static string GetDeviceId(uint inst)
    {
        IntPtr buffer = Marshal.AllocHGlobal(MAX_DEVICE_ID_LEN + 1);
        int cr = CM_Get_Device_ID(inst, buffer, MAX_DEVICE_ID_LEN + 1, 0);
        if (cr != 0)
            throw new Exception("CM Error:" + cr);

        try
        {
            return Marshal.PtrToStringAnsi(buffer);
        }
        finally
        {
            Marshal.FreeHGlobal(buffer);
        }
    }

    public string[] ChildrenPnpDeviceIds
    {
        get
        {
            if (IsVistaOrHiger)
                return GetStringListProperty(DEVPROPKEY.DEVPKEY_Device_Children);

            uint child;
            int cr = CM_Get_Child(out child, _data.DevInst, 0);
            if (cr != 0)
                return new string[0];

            List<string> ids = new List<string>();
            ids.Add(GetDeviceId(child));
            do
            {
                cr = CM_Get_Sibling(out child, child, 0);
                if (cr != 0)
                    return ids.ToArray();

                ids.Add(GetDeviceId(child));
            }
            while (true);
        }
    }

    private static bool IsVistaOrHiger
    {
        get
        {
            return (Environment.OSVersion.Platform == PlatformID.Win32NT && Environment.OSVersion.Version.CompareTo(new Version(6, 0)) >= 0);
        }
    }

    private const int INVALID_HANDLE_VALUE = -1;
    private const int ERROR_NO_MORE_ITEMS = 259;
    private const int MAX_DEVICE_ID_LEN = 200;

    [StructLayout(LayoutKind.Sequential)]
    private struct SP_DEVINFO_DATA
    {
        public int cbSize;
        public Guid ClassGuid;
        public uint DevInst;
        public IntPtr Reserved;
    }

    [Flags]
    private enum DIGCF : uint
    {
        DIGCF_DEFAULT = 0x00000001,
        DIGCF_PRESENT = 0x00000002,
        DIGCF_ALLCLASSES = 0x00000004,
        DIGCF_PROFILE = 0x00000008,
        DIGCF_DEVICEINTERFACE = 0x00000010,
    }

    [DllImport("setupapi.dll", SetLastError = true)]
    private static extern bool SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet, uint MemberIndex, ref SP_DEVINFO_DATA DeviceInfoData);

    [DllImport("setupapi.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    private static extern IntPtr SetupDiGetClassDevs(IntPtr ClassGuid, string Enumerator, IntPtr hwndParent, DIGCF Flags);

    [DllImport("setupapi.dll")]
    private static extern int CM_Get_Parent(out uint pdnDevInst, uint dnDevInst, uint ulFlags);

    [DllImport("setupapi.dll")]
    private static extern int CM_Get_Device_ID(uint dnDevInst, IntPtr Buffer, int BufferLen, uint ulFlags);

    [DllImport("setupapi.dll")]
    private static extern int CM_Get_Child(out uint pdnDevInst, uint dnDevInst, uint ulFlags);

    [DllImport("setupapi.dll")]
    private static extern int CM_Get_Sibling(out uint pdnDevInst, uint dnDevInst, uint ulFlags);

    [DllImport("setupapi.dll")]
    private static extern bool SetupDiDestroyDeviceInfoList(IntPtr DeviceInfoSet);

    // vista and higher
    [DllImport("setupapi.dll", SetLastError = true, EntryPoint = "SetupDiGetDevicePropertyW")]
    private static extern bool SetupDiGetDeviceProperty(IntPtr DeviceInfoSet, ref SP_DEVINFO_DATA DeviceInfoData, ref DEVPROPKEY propertyKey, out int propertyType, IntPtr propertyBuffer, int propertyBufferSize, out int requiredSize, int flags);

    [StructLayout(LayoutKind.Sequential)]
    private struct DEVPROPKEY
    {
        public Guid fmtid;
        public uint pid;

        // from devpkey.h
        public static readonly DEVPROPKEY DEVPKEY_Device_Parent = new DEVPROPKEY { fmtid = new Guid("{4340A6C5-93FA-4706-972C-7B648008A5A7}"), pid = 8 };
        public static readonly DEVPROPKEY DEVPKEY_Device_Children = new DEVPROPKEY { fmtid = new Guid("{4340A6C5-93FA-4706-972C-7B648008A5A7}"), pid = 9 };
    }

    private string[] GetStringListProperty(DEVPROPKEY key)
    {
        int type;
        int size;
        SetupDiGetDeviceProperty(_hDevInfo, ref _data, ref key, out type, IntPtr.Zero, 0, out size, 0);
        if (size == 0)
            return new string[0];

        IntPtr buffer = Marshal.AllocHGlobal(size);
        try
        {
            if (!SetupDiGetDeviceProperty(_hDevInfo, ref _data, ref key, out type, buffer, size, out size, 0))
                throw new Win32Exception(Marshal.GetLastWin32Error());

            List<string> strings = new List<string>();
            IntPtr current = buffer;
            do
            {
                string s = Marshal.PtrToStringUni(current);
                if (string.IsNullOrEmpty(s))
                    break;

                strings.Add(s);
                current += (1 + s.Length) * 2;
            }
            while (true);
            return strings.ToArray();
        }
        finally
        {
            Marshal.FreeHGlobal(buffer);
        }
    }

    private string GetStringProperty(DEVPROPKEY key)
    {
        int type;
        int size;
        SetupDiGetDeviceProperty(_hDevInfo, ref _data, ref key, out type, IntPtr.Zero, 0, out size, 0);
        if (size == 0)
            return null;

        IntPtr buffer = Marshal.AllocHGlobal(size);
        try
        {
            if (!SetupDiGetDeviceProperty(_hDevInfo, ref _data, ref key, out type, buffer, size, out size, 0))
                throw new Win32Exception(Marshal.GetLastWin32Error());

            return Marshal.PtrToStringUni(buffer);
        }
        finally
        {
            Marshal.FreeHGlobal(buffer);
        }
    }
}

Answer 3

There's an ancient Win32 API for device enumeration, it used to be part of the installer API but has fallen into disuse - I'm only aware of its existence, notsomuch its usage, but hopefully it'll be helpful:

http://msdn.microsoft.com/en-us/library/windows/hardware/ff551015(v=vs.85).aspx

The SP_DEVICE_INTERFACE_DETAIL structure is your end-goal: it has the actual device path. The path to get there, however... It'd all be PInvoke, and fairly nasty looking from the signatures, but here are some references:

The PInvoke signatures:

http://pinvoke.net/default.aspx/setupapi/SetupDiGetClassDevs.html http://pinvoke.net/default.aspx/setupapi/SetupDiEnumDeviceInterfaces.html http://pinvoke.net/default.aspx/setupapi/SetupDiGetDeviceInterfaceDetail.html

The structure mappings:

http://pinvoke.net/default.aspx/Structures/SP_DEVICE_INTERFACE_DATA.html http://pinvoke.net/default.aspx/Structures/SP_DEVICE_INTERFACE_DETAIL_DATA.html

Ooh, I found some example usage (in C++, but fairly translatable):

http://oroboro.com/usb-serial-number/