COM Ports im System auslesen

[christian.noeding]

Hi,


habe auch lange nach einer sauberen Methode gesucht. Diese hier erkennt alle COM-Ports und zeigt auch die Beschreibung an. Die COM-Ports werden bei meiner Funktion in die Combobox "portchange" eingefügt. Es wird die SetupAPI der Jedis benötigt:

Delphi-Quellcode:

procedure SearchSerialPorts;
const
  GUID_DEVINTERFACE_COMPORT: TGUID                = '{86e0d1e0-8089-11d0-9ce4-08003e301f73}';
  GUID_DEVINTERFACE_SERENUM_BUS_ENUMERATOR: TGUID = '{4D36E978-E325-11CE-BFC1-08002BE10318}';
var
  PnPHandle: HDEVINFO;
  DevData: TSPDevInfoData;
  DeviceInterfaceData: TSPDeviceInterfaceData;
  FunctionClassDeviceData: PSPDeviceInterfaceDetailData;
  Success: LongBool;
  Devn: Integer;
  BytesReturned: DWORD;
  SerialGUID: TGUID;
  Inst: DEVINST;
  RegKey: HKEY;
  RegBuffer: array [0..1023] of Char;
  RegSize, RegType: DWORD;
  FriendlyName: string;
  PortName: string;
  DeviceDescription: string;
  Bus: string;
begin
  // these API conversions are loaded dynamically by default
  LoadSetupApi;
  LoadConfigManagerApi;

  // enumerate all serial devices (COM port devices)
    SerialGUID := GUID_DEVINTERFACE_COMPORT; // GUID_DEVINTERFACE_SERENUM_BUS_ENUMERATOR;

  PnPHandle := SetupDiGetClassDevs(@SerialGUID, nil, 0, DIGCF_PRESENT or DIGCF_DEVICEINTERFACE);
  if PnPHandle = Pointer(INVALID_HANDLE_VALUE) then
    Exit;

  // Combobox klarmachen
  portchange.Items.BeginUpdate;
  portchange.Items.Clear;

  Devn := 0;
  repeat
    DeviceInterfaceData.cbSize := SizeOf(TSPDeviceInterfaceData);
    Success := SetupDiEnumDeviceInterfaces(PnPHandle, nil, SerialGUID, Devn, DeviceInterfaceData);
    if Success then
    begin
      DevData.cbSize := SizeOf(DevData);
      BytesReturned := 0;
      // get size required for call
      SetupDiGetDeviceInterfaceDetail(PnPHandle, @DeviceInterfaceData, nil, 0, BytesReturned, @DevData);
      if (BytesReturned <> 0) and (GetLastError = ERROR_INSUFFICIENT_BUFFER) then
      begin
        // allocate buffer and initialize it for call
        FunctionClassDeviceData := AllocMem(BytesReturned);
        FunctionClassDeviceData.cbSize := SizeOf(TSPDeviceInterfaceDetailData);

        if SetupDiGetDeviceInterfaceDetail(PnPHandle, @DeviceInterfaceData,
          FunctionClassDeviceData, BytesReturned, BytesReturned, @DevData) then
        begin
          // gives the friendly name of the device as shown in Device Manager
          FriendlyName := GetRegistryPropertyString(PnPHandle, DevData, SPDRP_FRIENDLYNAME);
          // gives a device description
          DeviceDescription := GetRegistryPropertyString(PnPHandle, DevData, SPDRP_DEVICEDESC);
          // now try to get the assigned COM port name
          RegKey := SetupDiOpenDevRegKey(PnPHandle, DevData, DICS_FLAG_GLOBAL, 0, DIREG_DEV, KEY_READ);
          RegType := REG_SZ;
          RegSize := SizeOf(RegBuffer);
          RegQueryValueEx(RegKey, 'PortName', nil, @RegType, @RegBuffer[0], @RegSize);
          RegCloseKey(RegKey);
          PortName := RegBuffer;
          Inst := DevData.DevInst;
          CM_Get_Parent(Inst, Inst, 0);
          Bus := ExtractBus(GetDeviceID(Inst));
            
          // COM-Ports in Combobox eintragen
          portchange.Items.Add(PortName + ' (' + DeviceDescription + ', ' + Bus+')');
        end;
        FreeMem(FunctionClassDeviceData);
      end;
    end;
    Inc(Devn);
  until not Success;
  SetupDiDestroyDeviceInfoList(PnPHandle);

  // Combobox freigeben
  portchange.Items.EndUpdate;

  // unload API conversions
  UnloadSetupApi;
  UnloadConfigManagerApi;
end;

Das führt dann zu dem Ergebnis im Anhang.




eine alternative Suchmethode, die allerdings keine Beschreibung des COM-Ports anzeigt:

Delphi-Quellcode:

// COM-Ports von 1 bis 16 abklappern
  portchange.Clear;
  for i:=1 to 16 do
  begin
    TestHandle := CreateFile(PChar('\\.\COM'+IntToStr(i)),GENERIC_READ or GENERIC_WRITE,0,nil,OPEN_EXISTING,FILE_FLAG_OVERLAPPED,LongInt(0));
    if (TestHandle > 0) then
    begin
      portchange.Items.Add('COM'+inttostr(i));
      CloseHandle(TestHandle);
    end;
  end;

Viel Erfolg,
Christian