Hi David,
Thank you for your interest in Syncfusion Products.
A summary row in a GridGroupingControl is a row that has column totals, averages, or some other type of summary information. A summary row is indispensable for a grid with many numbers. Please have a look at the sample below for Caption Summary demo,
http://samples.syncfusion.com/ASPNET/7.3.0.20/web/Grid.Grouping.Web/samples/3.5/Summary/SummaryInCaption/cs/summaryincaption.aspxThanks,
Rekha