Row numbers for computed fields When you refer to an control in a band other than the detail band (usually a computed field) you still specify a row number. For the header, footer, or summary, specify a row number of 1. For the group header or trailer, specify the group number:
If you specify nothing after the computed field name, you refer to the computed field DWObject, not the data. For a computed field that occurs more than once, you can get all values by specifying buffer or datasource instead of rownum, just as for columns.