How can i solve out of memory exception in list generic if adding new value

  foreach(DataColumn dc in dTable.Columns)
                foreach (DataRow dr in dTable.Rows)
                    myScriptCellsCount.MyCellsCharactersCount.Add(dr[dc].ToString().Length);

MyBase Class:

    public class MyExcelSheetsCells
    {
        public List<int> MyCellsCharactersCount { get; set; }

        public MyExcelSheetsCells()
        {
            MyCellsCharactersCount = new List<int>();
        }

    }