RDLC calculate running totals?

Question

I am struggling to get a running sum to work on a report. What I want is the following:

Product    Qty1   Qty2  Total  RunningTotal
ABC123     100    200   300    300
DEF321     50     100   150    450
XYZ123     -100   -150  -250   200

The total column is an expression like

=ReportItems!Qty1.value + ReportItems!Qty2.Value

For running total I have tried many different things, most of which tell me that it has to be in a header or footer. The obvious expression which I thought would work is

=ReportItems!Total.Value + previous(ReportItems!Total.Value)

but that doesnt work.

Can anyone explain what I am doing wrong here?

Cheers Dean

Answer 1

I believe you're looking for the RunningValue function. Untested, but something like:

=RunningValue(Fields!Total.Value,Sum,"MyGroupName")