Using Web.UI v2011.1.315.35
How can I count only non-blank items in the group
Screenshots attached using the built-in and custom aggregates, also the custom-aggregation event handler code attached.
I am afraid your goal could be achieved only using custom aggregate as you demonstrated in the project, but not using the built-in "Count" aggregate.
Hope you will find the answer :) i need it too
In the custom aggregation, the grid footer only contains values of last group.
In the built-in count, the group footer includes null values.