How can I apply any of these alternatives to my scenario: we have a column that is the cumulative sum of the values of another column, in the VISIBLE rows.
E.g. if I have 3 rows with values 1, 4, 8, the column I want will have the value 1 (first row's value), 5 (second row = 4 [value of second row] + 1 [cumulative value from first row]) and 13 (third row = 8 [value from third row] + 5 [cumulative result from second row]).
The problem is that the cumulative sum must be performed AFTER any filtering is applied, that is, after ToDataSourceResult() call.
How can I achieve it? I can do it before the call, as I have access to writable data, using a cycle through the entire contents. But, then, ToDataSourceResult() is called and I end up with a read-only IEnumerable.
Thank you for your help.