Set region and LOV properties dynamically

Question

Hello,
I am building a page with 2 LOV fields, and I need help for two parts.
My questions are:
: Where do I write code to control if region is showing / hiding?
: How do I change a bind-variable in my SQL-View-Object that is used in a LOV?
Details about my page:
I have a page with 2 regions.
- Region A
...LOV projectID
- Region B
...LOV subTaskID
I have added a basic Controller Object for Region A, and now I am stuck.
I want the page to work as:
1) When the user visits page first time, I want only Region A to show
....(the user must pick a ProjectID)
2) After selecting projectID and clicking a button, then page refreshes, and Region B shows as well.
....(so the user can pick a subTaskID)
The subTasks shown depend on the projectID selected
(I use a bind variable WHERE TABLE.projectID = :1 clause)
I don't know where to put the code to "make region visible / invisible".
And I don't know where to put code to change that bind variable in region B LOV VO
Thanks in advance for your help

Answer 1

Thanks for your help.
I have the system mostly working now.
However, now I'm stuck on the exact code for using my HashMap. I don't know how to take passed-values out of the HashMap and place them into Region A messageLOVInput field1 or messageTextInput field2
//Controller object: Function processRequest
super.processRequest(pageContext, webBean);
if(pageContext.getParameter("ProjectIDParam") != null)
String pID = pageContext.getParameter("ProjectIDParam");
String pNum = pageContext.getParameter("ProjectNumberParam");
// Now I'm stuck here - Can't set default values in messageLOVInput item or messageTextInput item
As review:
Added this code to Application Module Impl file
public void SetSalesLOVBindVariable(String givenProjectID)
..WORKTakeoffAMImpl thisAM =
....(WORKTakeoffAMImpl)this.getApplicationModule();
..OAPlsqlViewObjectImpl theVO =
....(OAPlsqlViewObjectImpl)thisAM.getWORKCustomLOV1();
..theVO.setWhereClauseParams(null);
..theVO.setWhereClauseParam(
....1,new String(givenProjectID));
Then I added this snippet to the processFormRequest for Region A:
String projectID = (String)pageContext.getParameter("ProjectID");
WORKTakeoffAMImpl am =
..(WORKTakeoffAMImpl)pageContext.getApplicationModule(webBean);
am.SetSalesLOVBindVariable(projectID);
HashMap params = new HashMap(2);
params.put("ProjectIDParam",
..(String)pageContext.getParameter("ProjectID"));
params.put("ProjectNumberParam",
..(String)pageContext.getParameter("SelectProjectLOV"));
pageContext.setForwardURLToCurrentPage(
..params,
..true, // retain the AM
..OAWebBeanConstants.ADD_BREAD_CRUMB_NO,
..OAWebBeanConstants.IGNORE_MESSAGES);