Serial (COM) ports name or identification

Question

I've a program that access multiple serial ports using cport.

To configure, till now I simply listed all available comports in a combobox to make a selection, but the increasing number of drivers with (virtual) serial interfaces makes configuring for end-users troublesome.

The current detection works with createfile(), but that has the problem that you only get exists/nonexists and maybe "busy" as information.

However to improve, I need per COM port a identification string, like the hardware device/driver (device manager) it is connected too. This would make it easier for the user to narrow the comports down (since we deliver a finite number of serial cards)

Probably it is available from WMI, but that's quite a jungle, does sb have more concrete information, or better, code?

(Delphi XE3, Win7+, no solution that requires additional installing or deployment please)

Answer 1

If you want enumerate the COM ports getting a friendly name you can use the SetupAPI and the GUID_DEVINTERFACE_COMPORT device interface class.

Try this sample

{$APPTYPE CONSOLE}

{$R *.res}

uses
  Windows,
  SysUtils,
  JvSetupApi;

const
  GUID_DEVINTERFACE_COMPORT:TGUID='{86E0D1E0-8089-11D0-9CE4-08003E301F73}';

procedure EnumerateCOMPorts;
var
   cbRequired : DWORD;
   hdev     : HDEVINFO;
   idev     : Integer;
   did      : TSPDeviceInterfaceData;
   pdidd    : PSPDeviceInterfaceDetailData;
   PropertyBuffer : array[0..255] of Char;
   DeviceInfoData: TSPDevInfoData;
   PropertyRegDataType: DWORD;
   RequiredSize: DWORD;
begin
  // enumerate the com ports
  hdev :=  SetupDiGetClassDevs(@GUID_DEVINTERFACE_COMPORT, nil, 0,  DIGCF_PRESENT OR DIGCF_DEVICEINTERFACE);
  if ( INVALID_HANDLE_VALUE <>  THandle(hdev) ) then
  begin
    try
      idev:=0;
      ZeroMemory(@did, SizeOf(did));
      did.cbSize := SizeOf(did);
      repeat
        if (SetupDiEnumDeviceInterfaces(hdev, nil, GUID_DEVINTERFACE_COMPORT, idev, did)) then
        begin
            cbRequired := 0;
            SetupDiGetDeviceInterfaceDetail(hdev, @did, nil, 0, cbRequired, nil);
           if (ERROR_INSUFFICIENT_BUFFER= GetLastError()) then
           begin
              pdidd:=AllocMem(cbRequired);
              try
                pdidd.cbSize := SizeOf(TSPDeviceInterfaceDetailData);
                DeviceInfoData.cbSize:= SizeOf(DeviceInfoData);
                RequiredSize:=0;
                if (SetupDiGetDeviceInterfaceDetail(hdev, @did, pdidd, cbRequired, RequiredSize, @DeviceInfoData)) then
                begin

                 PropertyRegDataType:=0;
                 RequiredSize:=0;
                 if SetupDiGetDeviceRegistryProperty(hdev, DeviceInfoData, SPDRP_FRIENDLYNAME, PropertyRegDataType,  PBYTE(@PropertyBuffer[0]), SizeOf(PropertyBuffer), RequiredSize) then
                  Writeln(Format('Friendly Name - %s',[PropertyBuffer]));

                 if SetupDiGetDeviceRegistryProperty(hdev, DeviceInfoData, SPDRP_DEVICEDESC, PropertyRegDataType,  PBYTE(@PropertyBuffer[0]), SizeOf(PropertyBuffer), RequiredSize) then
                  Writeln(Format('Description   - %s',[PropertyBuffer]));

                 if SetupDiGetDeviceRegistryProperty(hdev, DeviceInfoData, SPDRP_LOCATION_INFORMATION, PropertyRegDataType,  PBYTE(@PropertyBuffer[0]), SizeOf(PropertyBuffer), RequiredSize) then
                  Writeln(Format('Location      - %s',[PropertyBuffer]));
                end
                else
                RaiseLastOSError;
              finally
                FreeMem(pdidd);
              end;
           end;
        end
        else
        Break;
        inc(idev);
      until false;
    finally
      SetupDiDestroyDeviceInfoList(hdev);
    end;
  end;
end;

begin
  try
    if not LoadsetupAPI then exit;
     EnumerateCOMPorts;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
  readln;
end.

This will return something like so

Note : The JvSetupApi unit is part of the JVCL library.