tree checkboxes SaveItem

CREATE PROCEDURE [dbo].[fm_tst-form-treeview_saveItem]
   @username nvarchar(256),
   @itemID int,
   @parameters ExtendedDictionaryParameter READONLY
AS
BEGIN

    declare @pf1 nvarchar(max)
    select @pf1 = Value2 from @parameters where [key]='f1'

    exec as_print @str = @pf1

    update tst_categories
    set selected= 0

    update tst_categories
    set selected= 1
    where id in (select Value from dbo.split(@pf1,',') where Value<>'')

    -- SELECT 1 (Result, Msg, SuccessUrl, HideFormAfterSubmit, RefreshContainer)
    select 1 Result, 'OK' Msg, '' SuccessUrl, 0 HideFormAfterSubmit, '' RefreshContainer
END