Pagination and sorting dynamically in SQLserver 2005/2008

Hi this article show you how to do pagination and dynamically sorting the result ascending or descending from the selection list in sql 2005/2008

Create PROCEDURE [dbo].[usp_get_all_groups] 
    -- Add the parameters for the stored procedure here
    @pStartIndex smallint,
    @pPageSize tinyint,
    @pOrderBy varchar(15)
AS
BEGIN

 SELECT *
 FROM
  (SELECT ROW_NUMBER() OVER (ORDER BY 
      CASE WHEN @pOrderBy='GroupId ASC' THEN UserGroups._id END ASC,  
      CASE WHEN @pOrderBy='GroupId DESC' THEN UserGroups._id END DESC,             
      CASE WHEN @pOrderBy='GroupCode ASC' THEN UserGroups.GroupCode END ASC,
      CASE WHEN @pOrderBy='GroupCode DESC' THEN UserGroups.GroupCode END DESC) AS Row, 
      * FROM UserGroups) AS StudentsWithRowNumbers
  WHERE Row>= @pStartIndex AND Row <= @pStartIndex + @pPageSize
  ORDER BY Row      END

Here to execute the procedure 
DECLARE @return_value int
EXEC    @return_value = [dbo].[usp_get_all_groups]
        @pStartIndex = 0,
        @pPageSize = 15,
        @pOrderBy = N'GroupCode ASC'
SELECT  'Return Value' = @return_value

Result
Row _id GroupCode   Description Type    IsActive1   1   CS2009  CS 2009 Batch   S   1
2   2   IT2009  IT 2009 Batch   S   1
3   3   ME2009  ME 2009 Batch   S   1
4   4   EC2009  EC 2009 Batch   S   1
5   5   EE2009  EE 2009 Batch   S   1
6   8   CS_F    CS Faculties    F   1
7   9   IT_F    IT Faculties    F   1
8   10  ME_F    ME Faculties    F   1
9   11  EC_F    EC Faculties    F   1
10  12  EE_F    EE Faculties    F   1
11  13  BSC_F   Basic Science Faculties F   1
12  14  Accounts    Accounts    A   1
13  15  Mgmt    Management  M   1
14  16  Lib Library B   1
15  17  TnP Training & Placement    T   1