CustomData Element (RDL)
Represents the data to display in a custom report item.
The CustomData element defines the data to be handed to a custom report item and the way that data should be grouped, sorted, filtered and aggregated. Custom report items with a CustomData element are considered to be DataRegions. This impacts such things as restricting placement within the report (for example, custom report items not allowed in detail rows, page header or page footer), available scopes for expressions, and the use of the RepeatWith element.