function

overload

type
  TXLSCellWriteEvent = procedure(
    Sender: TObject;
    SheetIndex, Row, Col: Integer;
    var Value: Variant;
    var Skip: Boolean;
    var Cancel: Boolean) of object;

function WriteCells(ARange: WideString; Callback: TXLSCellWriteEvent): Integer; overload;
function WriteCells(ARow1, ACol1, ARow2, ACol2: Integer; Callback: TXLSCellWriteEvent): Integer; overload;

. The numeric overload uses 1-based row and column indexes. Ranges are normalized when the start row or column is greater than the end row or column

end

procedure TForm1.WriteCell(Sender: TObject; SheetIndex, Row, Col: Integer;
  var Value: Variant; var Skip: Boolean; var Cancel: Boolean);
begin
  if Col = 3 then
  begin
    Skip := True;
    Exit;
  end;

  Value := Format('R%dC%d', [Row, Col]);
  if Row >= 1000 then
    Cancel := True;
end;

Written := Workbook.Sheets[1].WriteCells('A1:D2000', WriteCell);

'R%dC%d'