How to get Usb ComPorts in C#?

Question

Basically I'm working on a small project which involve serial message transfer. I tried GetPortNames() method in C#. It sends Standard Serial Over Bluetooth links instead of Com Ports or USB Ports what to do?

Answer 1

You can get anything with SetupDi APIs and use the right GUID to filter them

For example with GUID_DEVINTERFACE_COMPORT :

                //IntPtr hDeviceInfo = SetupDiGetClassDevs(ref GUID_DEVINTERFACE_USB_HUB, IntPtr.Zero, IntPtr.Zero, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
                IntPtr hDeviceInfo = SetupDiGetClassDevs(ref GUID_DEVINTERFACE_COMPORT, IntPtr.Zero, IntPtr.Zero, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
                if (hDeviceInfo != IntPtr.Zero)
                {
                    var DeviceInfoData = new SP_DEVINFO_DATA() { cbSize = Marshal.SizeOf(typeof(SP_DEVINFO_DATA)) };
                    int nNumberOfDevicesPresent = 0;
                    while (SetupDiEnumDeviceInfo(hDeviceInfo, nNumberOfDevicesPresent, ref DeviceInfoData))
                    {
                        StringBuilder sbDeviceName = new StringBuilder(260); 
                        bool bRet = SetupDiGetDeviceRegistryProperty(hDeviceInfo, ref DeviceInfoData, SPDRP_FRIENDLYNAME, 0, sbDeviceName, (uint)sbDeviceName.Capacity, IntPtr.Zero);
                        if (bRet)
                        {
                            Console.WriteLine("Device Name : {0}", sbDeviceName.ToString());                           
                        }
                        else
                        {
                            bRet = SetupDiGetDeviceRegistryProperty(hDeviceInfo, ref DeviceInfoData, SPDRP_DEVICEDESC, 0, sbDeviceName, (uint)sbDeviceName.Capacity, IntPtr.Zero);
                            if (bRet)
                            {                                
                                Console.WriteLine("Device Description : {0}", sbDeviceName.ToString());                               
                            }
                        }
                        nNumberOfDevicesPresent++;
                    }
                }

With :

      public static Guid GUID_DEVINTERFACE_COMPORT = new Guid("{86E0D1E0-8089-11D0-9CE4-08003E301F73}");
      public static Guid GUID_DEVINTERFACE_USB_HUB = new Guid("{f18a0e88-c30c-11d0-8815-00a0c906bed8}");

      [DllImport("Setupapi.dll", CharSet = CharSet.Unicode, SetLastError = true)]
      public static extern IntPtr SetupDiGetClassDevs(ref Guid ClassGuid, IntPtr Enumerator, IntPtr hWndParent, int Flags);

      public const int DIGCF_PRESENT = 0x00000002;
      public const int DIGCF_DEVICEINTERFACE = 0x00000010;
      public const int ERROR_INSUFFICIENT_BUFFER = 122;
      
    	#if WIN64
        public const int PACK_SIZE = 8;
			#else
        public const int PACK_SIZE = 1;
			#endif
      [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode, Pack = PACK_SIZE)]
      public struct SP_DEVINFO_DATA
      {
          public int cbSize;
          public Guid ClassGuid;
          public int DevInst;
          public IntPtr Reserved;
      }
      
      [DllImport("Setupapi.dll", CharSet = CharSet.Unicode, SetLastError = true)]
      public static extern bool SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet, int MemberIndex, ref SP_DEVINFO_DATA DeviceInfoData);

      [DllImport("Setupapi.dll", CharSet = CharSet.Unicode, SetLastError = true)]
      public static extern bool SetupDiGetDeviceRegistryProperty(IntPtr DeviceInfoSet, ref SP_DEVINFO_DATA DeviceInfoData, uint Property,
          uint PropertyRegDataType, StringBuilder PropertyBuffer, uint PropertyBufferSize, IntPtr RequiredSize);

      public const int SPDRP_DEVICEDESC = (0x00000000);  // DeviceDesc (R/W)
      public const int SPDRP_FRIENDLYNAME = (0x0000000C); // FriendlyName (R/W)
      public const int SPDRP_LOCATION_INFORMATION = (0x0000000D);  // LocationInformation (R/W)