Hold/Save Value with Visaul Studio Function

Hi,

i have a problem with a RTC Report.

At the Report 722 "Phys. Inventory List" I added the expression, that every 2nd row has another color.
Works for the standard fine.

Now, we have the option, that we could print the Lot No./ Serial No. for the Items.
For that row which has Serial Nos. or Lot Nos., the RowNumber() Function returns the actual RowNumber + the Sum of the Serial NO./ Lot No. rows.
e.x. the 4th row hast 7 serial no. rows. The function returns 11. That has the effect, that two rows in a row are (not) colored.

Does anybody has an idea, how can I solve it?

My first idea was:

I add a function which checks, if the last row no. was odd or even. My problem here is, that I cannot store the last row number.
My function looks like this:

shared lastRowNo as Integer
public ReturnRowNo as Integer

public function CheckRowNumber(RowNo as Integer) as Integer
  if  lastRowNo <> 0 then
    if lastRowNo mod 2 = 0 and RowNo mod 2 = 0 then 
      ReturnRowNo = RowNo + 1
    end if
    if lastRowNo mod 2 <> 0 and RowNo mod 2 <> 0 then 
      ReturnRowNo = RowNo + 1
    end if 
  else 
    ReturnRowNo = RowNo
  end if
  
  lastRowNo = RowNo
  return ReturnRowNo

end function 

Any ideas, how i can store the value

Thanks in advance

rom