Dynamic WHERE Clauses

So how do you do dynamic WHERE clauses with asp.net?

 I have a QueryString parameter with a value that will look like this.  |1|  or  |1||2|  or  |1||2||3|  or etc.  For each number in the value I want to add an EXISTS function to the WHERE clause.  I have accomplished this in T-SQL.  But I can't figure out how to bind asp.net control to it.  It gives me 'Invalid syntax near the keyword 'ORDER'.  I know this has something to do with .net not being able to exaluate the schema properly.

So I tried Linq to Sql.  Well, so happens that my WHERE clause is pointing to the existance of records in another table which the default install of Linq to Sql doesn't seam to support.  I came across this post (http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=2979081&SiteID=1) that explains how to dynamically query across multiple tables.  I tried this and got errors when trying to plug in the additional code.  And this still does not let me dynamically add where clauses.

 I tried the who Predicate thing and ran into the same problem where I can't reference the existance of values in foreign tables.

 Here is my sproc.  Can anyone tell me how to get this into a asp.net environment.  I also do NOT want to auto-generate fields in my GridView.ALTER PROCEDURE dbo.Item_SelectByFilters      @Item_Category_Id int = NULL,       @ItemSpecificValueIdList varchar(100) = NULL,       @debug bit = 0 AS DECLARE @sql        nvarchar(4000),        @paramlist  nvarchar(4000) SELECT @sql = 'SELECT     Item_Id, Number, Primary_Item_Category_Id, Secondary_Item_Category_Id, Engineering_Document_Id, CategoryIdList              FROM         Item              WHERE     (1 = 1)' IF @Item_Category_Id IS NOT NULL SELECT @sql = @sql + ' AND                                           Item.CategoryIdList Like ''|'' + CONVERT(varchar, (@xItem_Category_Id) + ''|''' IF @ItemSpecificValueIdList IS NOT NULL       BEGIN            WHILE @ItemSpecificValueIdList <> ''            BEGIN                  DECLARE @StartLocation int                  SELECT @StartLocation = CHARINDEX('-', @ItemSpecificValueIdList, 1)                  IF @StartLocation <> 0                        BEGIN                              DECLARE     @EndLocation int                              SELECT @EndLocation = CHARINDEX('|', @ItemSpecificValueIdList, @StartLocation + 1)                              IF @EndLocation <> 0                                     BEGIN                                          DECLARE @ValueLength int                                          SELECT @ValueLength = @EndLocation - @StartLocation - 1                                          DECLARE @ValueBetween varchar(10)                                          SELECT @ValueBetween = SUBSTRING(@ItemSpecificValueIdList, @StartLocation + 1, @ValueLength)                                          IF @ValueBetween IS NOT NULL SELECT @sql = @sql + ' AND                                           EXISTS(SELECT Item_Specific_Value_Id FROM Item_Specific_Value WHERE Item_Id = Item.Item_Id AND Item_Specific_Value.Item_Specific_Value_Id = ' + @ValueBetween + ')'                                    END                        END                  SET @ItemSpecificValueIdList = SUBSTRING(@ItemSpecificValueIdList, @EndLocation + 1, len(@ItemSpecificValueIdList) - @EndLocation)            END      END SELECT @sql = @sql + '                     ORDER BY Item.Number' IF @debug = 1   PRINT @sql SELECT @paramlist = '@xItem_Category_Id int' 
EXEC sp_executesql @sql, @paramlist, @Item_Category_Id