HOW TO MAKE ITEM UPDATABLE/NON-UPDATABLE DYNAMICALLY

Question

Hi ,
I have a form with tabular layout on a multi record lock .
From shows 20 records at a time and there is a scroll bar to scroll down .There is an item "flag" in the block which is not visible in the form with values "Y" or "N" .
I need to make some text items in the record updatable when that record has "flag" ="Y" .Documentation say's we need to use set_item_instance_property to do that .
I tried it in when-new-record-instance,pre-query and key-exeqry triggers with no luck .
I would really appreciate if you could give me the following info
1) How to loop through each record in a block to check value of "flag"
2) Which trigger to use and level form,block etc .
Thanks,

Answer 1

Ram,
Thanks for the update . Now it works . Another problem though ...
My form displays 20 records at a time and I have a scroll bar .
I need to change the background of Item to white when it is updatable and gary when it is not updatable .
I've created a visual attribute and was using it with set_item_instance_property like this ..
declare
last_rec number;
begin
last_record;
last_rec := :system.cursor_record;
first_record;
for i in 1 .. last_rec
loop
if :ANNUAL_FUNDS.flag != 'Y' then
begin
Set_Item_Instance_Property( 'EXP_FUNDS', CURRENT_RECORD, UPDATE_ALLOWED , PROPERTY_FALSE);
Set_Item_Instance_Property( 'EXP_FUNDS', CURRENT_RECORD, VISUAL_ATTRIBUTE, 'VI_UPDATE');
end;
end if;
if :system.last_record = 'TRUE' or i = last_rec then
exit;
else
next_record;
end if;
end loop;
FIRST_RECORD;
end;
When I took out the loop the way you've mentioned
it's changing the background color of the item for the record in which cursor is in . Users want to look at the screen in a glance and go directly to the item which is updatable .
Is there any way we can loop through all records once and change properties in one shot ?
Sorry to bother you,
Asha