public void AddRow(RowType row) { if (row.Count != ColsCount) { string message = String.Format("AddRow: row to be added count ({0}) does not match the number of columns ({1}) in the CSVData", row.Count, ColsCount); throw new ArgumentOutOfRangeException(nameof(row), message); } else { _rows.Add(row.Select(x => x).ToList()); } }