public static IEnumerable <DataRow> GetRows(this DataTableCollection tables, int tableNumber) =>
 tables == null ? new List <DataRow>() :
 tables
 .GetTable(tableNumber)
 .Rows
 .Cast <DataRow>()
 .ToList();
 public static IEnumerable <DataColumn> GetColumns(this DataTableCollection tables, int tableNumber) =>
 tables == null ? new List <DataColumn>() :
 tables
 .GetTable(tableNumber)
 .Columns
 .Cast <DataColumn>()
 .ToList();