Updates group summaries.
Group summary values are automatically updated when changing cell values. There may be cases, however, when summary values do not only depend on the data displayed by the View. This may occur, for example, when calculating summary values manually using the GridControl.CustomSummary event. In this case, you need to update group summaries manually when changing external data that affects summary values. Call the UpdateGroupSummary method for this purpose.
The UpdateGroupSummary method iterates through all groups within the current View and recalculates summary values for each group. Note that when a View contains a large number of records, calling the UpdateGroupSummary method may cause a significant performance impact.