Ungroups data by the values of the current column.
Grid Views support grouping data by an unlimited number of columns. The UnGroup method cancels data grouping by the values of the given column. Calling this method has no effect if data is not grouped by the values of this column. If it is necessary to completely clear grouping, call the View's GridView.ClearGrouping method.
You can also ungroup data by the values of a single column by setting the column's GridColumn.GroupIndex property to -1.
To group data by a column, use the column's GridColumn.Group method.