'宣言
Public Class _DefaultGroupingsSorter (Of TKey As DataValueType, TGrouping As IGrouping(Of TKey)) Inherits _GroupingsSorter(Of TKey,TGrouping) Implements ISorter
public class _DefaultGroupingsSorter<TKey,TGrouping> : _GroupingsSorter<TKey,TGrouping>, ISorter where TKey: DataValueType where TGrouping: IGrouping<TKey>