public static System.Data.OrderedEnumerableRowCollection <TRow> ThenBy <TRow, TKey>(this System.Data.OrderedEnumerableRowCollection <TRow> source, System.Func <TRow, TKey> keySelector, System.Collections.Generic.IComparer <TKey> comparer)
 {
     throw null;
 }
 public static System.Data.OrderedEnumerableRowCollection <TRow> ThenBy <TRow, TKey>(this System.Data.OrderedEnumerableRowCollection <TRow> source, System.Func <TRow, TKey> keySelector)
 {
     throw null;
 }