Display multiple parameters in report header

Question

i am attempting to display a multiple parameter selection in my report header
i user
join({?parameter},",")
in the stored proc it is a varchar
in the formula editor i receive this error
a string array is required here
what do i need to do to display the selected parameter values
i have used this function before with varchars and have had no problems

Answer 1

i used the following syntax in my sp which produced the correct results. i just placed the parameter in the header without using the join function and it works like a charm.
ALTER   PROCEDURE [dbo].[Pr_orn_whse_rcpts]          
     (@From_Crt_Dte     datetime ,
      @To_Crt_Dte     datetime,
     @whse          varchar(90))
AS          
CREATE TABLE #T_Localwhs
     warehouse varchar(6) null
DECLARE
     @var     varchar(6),
     @i     numeric,
     @whs     varchar(6),
     @chk     numeric
SET @i = 1
SET @var = (charindex(',',@whse))
IF @var <> 0
     BEGIN
     WHILE (@i < @var)
          BEGIN
               --SET @var = (CHARINDEX(',',@whse))
               SET @whs = LTRIM(LEFT(@whse, (@var-1)))
               INSERT #T_Localwhs (warehouse) VALUES (@whs)
               SET @whse = RIGHT(@whse, (LEN(@whse)-@var))
               SET @var = (CHARINDEX(',',@whse))
          END
     INSERT #T_Localwhs (warehouse) VALUES (LTRIM(@whse))
     END
ELSE
     BEGIN
     INSERT #T_Localwhs (warehouse) VALUES (LTRIM(@whse))
     END
then you add a nested query to join it to the sp. as below. above your where statement.
JOIN     
          SELECT DISTINCT
               Warehouse
          FROM      #T_Localwhs
          ) TW
     ON     in_wthdr_tbl.in_wthdr_frwhs = TW.warehouse
WHERE