Prevents summaries from being calculated until the GridView.EndSummaryUpdate method is called.
Whenever summary items are added to a Grid View or their settings are modified, the grid automatically recalculates summaries. To prevent summary calculation until all summary items are properly initialized, use the BeginSummaryUpdate and GridView.EndSummaryUpdate methods. Enclose you code with these methods. The BeginSummaryUpdate method locks summary calculation; the GridView.EndSummaryUpdate method unlocks summary calculation and forces the grid to recalculate the current summaries.