SSRS Alternating Row Colour Within Groups

Question

I have a ssrs table report with row grouping and I would like to know how to change the colours of rows in groups without changing the background colour of the group column itself. With the answers I have found and implemented I get the effect of the second table in the picture when I want the effect of the first table:

Any help will be much appreciated.

This is a picture of the actual report and it's grouping:

Answer 1

The RowNumber technique only works on the Details group i.e. the lowest level group (with no Group columns defined). Think of it as returning the Row in the Dataset.

Instead I would write an expression that calculates the equivalent to RowNumber, but for the Group level - typically something using RunningValue ... CountDistinct on the Group Key field, like this:

= Iif ( RunningValue ( Fields!tableid.Value , CountDistinct , "TheNameOfYourGroup") Mod 2 = 0, "White", "WhiteSmoke")