Like the Data band, the Group Header band has three specific events:
BeginRenderEvent,
EndRenderEvent and
RenderingEvent.
BeginRenderEvent
The BeginRenderEvent is called before a group is rendered, in other words whenever a new group is output. This event can be used for the initialization of data or variables, or for calling certain actions.
EndRenderEvent
The EndRenderEvent is called after the group is output. Usually in the handler for this event data processing and the calculation of totals is done.
RenderingEvent
The RenderingEvent is called when the engine is rendering one data row from a group.