How to use P_SESSION.GET_VALUE_AS_VARCHAR2 in MDform item default Value

Question

I have a master detail form based on two tables. In the DETAIL_BLOCK section I have an item named 'APPROVAL_STATUS' based on the column of the same name in the underlying table. I have an unassociated textbox named CURR_APPROVSTAT in the detail form for which I would like to set it's default value to the current value of APPROVAL_STATUS when the master detail form is opened in %3D mode via a hyperlink.
I have tried using the p_session.get_value_as_varchar2 in the default value field of the CURR_APPROVSTAT item, but it generates errors on run.
EX:
Item CURR_APPROVSTAT
default value field
p_session.get_value_as_varchar2(
p_block_name => 'DETAIL_BLOCK',
p_attribute_name => 'APPROVAL_STATUS')
Default Value type:
Function returns varchar2
on run, it generates error that p_session must be declared (I get the same error if I use portal.p_session... also).
default value field
select p_session.get_value_as_varchar2(p_block_name => 'DETAIL_BLOCK', p_attribute_name => 'APPROVAL_STATUS')from dual
Default Value type:
SQL returns varchar2
on run, it generates and error that a right parenthesis is missing.
I have also tried using the following in the Additional PL/SQL - before displaying form:
p_session.set_value
(p_block_name => 'DETAIL_BLOCK'
,p_attribute_name => 'CURR_APPROVSTAT'
,p_value => p_session.get_value_as_varchar2(
p_block_name => 'DETAIL_BLOCK',
p_attribute_name => 'APPROVAL_STATUS')
on run, this generates the error identifier 'P_SESSION.GET_VALUE_AS_VARCHAR2' must be declared
My questions are:
1) is it possible to use the p_session.get_value_as_varchar2 in the default value field?
2) If yes, then what if the proper syntax
3) If no, can I set this value when the MD form opens from the additional pl/sql triggers, and if so, what is the syntax?
any assistance you can offer is greatly appreciated.
Sincerely,
ARM

Answer 1

In my detail block I have 10 rows displaying that may or may not have data after querying. To set the default value in the detail block, you have to set the index value of p_session.set_value. Since I don't know how many rows are already populated, I'm setting the default value to all 10 rows. Is there a better approach?
Here's my code example, which I've placed in the additional PL/SQL section before displaying the form...
DECLARE
l_district_id VARCHAR2(7);
BEGIN
l_district_id := p_session.get_value_as_varchar2
(p_block_name => 'MASTER_BLOCK',
p_attribute_name => 'A_DISTRICT_ID');
FOR i in 1 .. 10 LOOP
p_session.set_value
(p_block_name => 'DETAIL_BLOCK',
p_attribute_name => 'A_DISTRICT_ID',
p_value => TO_CHAR(l_district_id), p_index => i);
END LOOP;
END;