The Group method forces the control to re-group the items. The AllowGroupBy property specifies whether the control supports Group-By feature. The Group method has no effect if the AllowGroupBy property is False. The Ungroup method un-groups the items in the control's list. During execution any of these methods, the IsGrouping property returns True.  You can call the SortOrder property to sort and group by specified column. Use the SortType property to determine the way how the column is sorted. The ViewItemUpdate(exAddGroupItem) event is fired when a new grouping items is added to the control's list. You can use the ViewItemUpdate(exAddGroupItem) event, to add headers or footers during grouping, customize the aggregate formula to be displayed on different columns, while dropping a column to the sortbar. The Column.AllowGroupBy property may be used to prevent grouping a specific column. The AllowSort property indicates whether the user can sort a column by clicking the column's header.