In addition to displaying summaries/results from aggregates in the group header, RadGrid exposes group footers feature which provides the option to render footer under each group in the grid. The type of this footer item is GridGroupFooterItem. To enable this functionality merely set the ShowGroupFooter property of the respective GridTableView instance to true (its default value is false).
RadGrid also gives you the opportunity to retain the visibility of the group footers when their corresponding group header row is collapsed. In order to switch on this feature, just set the GroupingSettings.RetainGroupFooterVisibilityproperty to true.
The group footers are most commonly used to visualize calculations from aggregate functions within the scope of the current group. Furthermore, with nested groups you will have group footer for each inner group along with one for the main group. Aggregate calculations are supported for GridBoundColumns, GridCalculatedColumns and GridTemplateColumns.
In order to specify how the group aggregates will be evaluated, specify in every GridBoundColumn/GridCalculatedColumn/GridTemplateColumn the Aggregate property which accepts values from the GridAggregateFunction enumeration.
RadGrid will calculate aggregates over the entire data source and will respect the filter expression applied (if present).