Oracle JHeadstart Developer's Guide - Downloads - Oracle

6.12.2. Cascading Lists
• You cannot use the token $DEPENDS_ON_ITEM_VALUE$ if the item depends
on multiple other items. Instead, use the following expressions depending on the
layout style and search area of the group:
Item usage Expression
Table layout row.
Form layout bindings..inputValue
Search area search.criteria.
For example, to refer to the value of the JobId in the search area, use the
expression #{searchEmployees.criteria.EmployeesJobId}.
• If in your application you have more than one of the abovementioned item
usages, for example you have the dependency in both form layout and search
area, you will have to create multiple dependent items: one for each usage. Make
sure the copied dependent item is displayed only in table layout, or only in the
form layout, or only in the search area, and use the appropriate expression for
each copied item.
If the displayed values in a dropdown list depend on the chosen value in another
dropdown list, we call them cascading lists.
Here are the basic steps to generate this in a form layout using the Region-Countries
example from the HR schema:
• Create a ViewObject on Countries with a where clause named bind param:
region_id = :p_region_id
• define p_region_id on the Bind Params tab of your VO
• Set the Query Bind Parameter property in the dynamic domain created for the
country item drop down list according to the table below, for example:
p_region_id=#{bindings.CountriesRegionId.inputValue}
Item usage Expression
Table layout row.
Form layout bindings..inputValue
Search area search.criteria.
Attention: If you have the same cascading lists in table and form layout,
and/or in a search area, you need to make separate domains, and separate
items for CountryId: one displayed in table layout with the "table" domain
associated, one in form layout with the "form" domain associated, one in
search are with the "search area" domain associated.
6- 34 Generating User Interface Widgets JHeadstart Developer’s Guide