Delphi function for sending an email using MAPI

uses

  MAPI;

function SendMailMAPI(const Subject, Body, FileName, SenderName, SenderEMail,

                  RecepientName, RecepientEMail: String) : Integer;

var

  message: TMapiMessage;

  lpSender,

  lpRecepient: TMapiRecipDesc;

  FileAttach: TMapiFileDesc;

  SM: TFNMapiSendMail;

  MAPIModule: HModule;

begin

  FillChar(message, SizeOf(message), 0);

  with message do

  begin

    if (Subject<>'') then

    begin

      lpszSubject := PChar(Subject)

    end;

    if (Body<>'') then

    begin

      lpszNoteText := PChar(Body)

    end;

    if (SenderEMail<>'') then

    begin

      lpSender.ulRecipClass := MAPI_ORIG;

      if (SenderName='') then

      begin

        lpSender.lpszName := PChar(SenderEMail)

      end

      else

      begin

        lpSender.lpszName := PChar(SenderName)

      end;

      lpSender.lpszAddress := PChar('SMTP:'+SenderEMail);

      lpSender.ulReserved := 0;

      lpSender.ulEIDSize := 0;

      lpSender.lpEntryID := nil;

      lpOriginator := @lpSender;

    end;

    if (RecepientEMail<>'') then

    begin

      lpRecepient.ulRecipClass := MAPI_TO;

      if (RecepientName='') then

      begin

        lpRecepient.lpszName := PChar(RecepientEMail)

      end

      else

      begin

        lpRecepient.lpszName := PChar(RecepientName)

      end;

      lpRecepient.lpszAddress := PChar('SMTP:'+RecepientEMail);

      lpRecepient.ulReserved := 0;

      lpRecepient.ulEIDSize := 0;

      lpRecepient.lpEntryID := nil;

      nRecipCount := 1;

      lpRecips := @lpRecepient;

    end

    else

    begin

      lpRecips := nil

    end;

    if (FileName='') then

    begin

      nFileCount := 0;

      lpFiles := nil;

    end

    else

    begin

      FillChar(FileAttach, SizeOf(FileAttach), 0);

      FileAttach.nPosition := Cardinal($FFFFFFFF);

      FileAttach.lpszPathName := PChar(FileName);

      nFileCount := 1;

      lpFiles := @FileAttach;

    end;

  end;

  MAPIModule := LoadLibrary(PChar(MAPIDLL));

  if MAPIModule=0 then

  begin

    Result := -1

  end

  else

  begin

    try

      @SM := GetProcAddress(MAPIModule, 'MAPISendMail');

      if @SM<>nil then

      begin

        Result := SM(0, Application.Handle, message, MAPI_DIALOG or

                     MAPI_LOGON_UI, 0);

      end

      else

      begin

        Result := 1

      end;

    finally

      FreeLibrary(MAPIModule);

    end;

  end

  if Result<>0 then

  begin

    MessageDlg('Error sending mail ('+IntToStr(Result)+').', mtError, [mbOk],

               0)

  end;

end;