private void viewData() {
  dtData.CustomDrawRowIndicator += (s, e) =>
            {
                if (e.Info.IsRowIndicator && e.RowHandle >= 0)
                    e.Info.DisplayText = (e.RowHandle + 1).ToString();
            };

            dtData.IndicatorWidth = 50;
}

 private void viewData() {
  dtData.CustomDrawRowIndicator += (s, e) =>
            {
                if (e.Info.IsRowIndicator && e.RowHandle >= 0)
                    e.Info.DisplayText = (e.RowHandle + 1).ToString();
            };

            dtData.IndicatorWidth = 50;
}