從 PID/VID 換算出 GUID 值

public string GetGUID(string VendorID, string ProductID)

        {

            string m_GUID = "";

            ManagementObjectCollection USBControllerDeviceCollection = new ManagementObjectSearcher("SELECT * FROM Win32_USBControllerDevice").Get();

            if (USBControllerDeviceCollection != null)

            {

                foreach (ManagementObject USBControllerDevice in USBControllerDeviceCollection)

                {

                  String Dependent = (USBControllerDevice["Dependent"] as String).Split(new Char[] { '=' })[1];

                    if (Dependent.IndexOf(VendorID) >= 0 && Dependent.IndexOf(ProductID) >= 0)

                    {

                        ManagementObjectCollection PnPEntityCollection = new ManagementObjectSearcher("SELECT * FROM Win32_PnPEntity WHERE DeviceID=" + Dependent).Get();

                        if (PnPEntityCollection != null)

                        {

                            foreach (ManagementObject Entity in PnPEntityCollection)

                            {

                                Guid theClassGuid = new Guid(Entity["ClassGuid"] as String);    // ??安??GUID 

                                m_GUID = theClassGuid.ToString();

                                return m_GUID;

                            }

                          }

                    }

                }

            }

            return m_GUID;

}