VScroll Bar and Tree Issue

Question

I have a tree component and am using a custom DataDescriptor,
when I dynamically add data to the DataProvider, I have a set that
does not show in the tree. When those items get added, the
VScrollBar will show. But since the items are 'hidden' and do not
show in the tree view, the VScrollBar should not be showing. If I
expand an item in the tree, then the VScrollBar will disappear and
the tree will look like it is supposed to be.
I tried using (individually and in combination)
invalidateSize(), invalidateDisplayList(), invalidateProperties(),
and invalidateList() on the tree but it doesnt update the
VScrollBar like it should.
Any help would be greatly appreciated, thanks.
Art

Answer 1

Arty,
My issue is i'm not getting Vscrollbar on dynamic
loading(lazy loading). I'm using flex 3 with cairngorm framework.
Loading all children(dynamically) in getchildren method of
datadescriptor. Here is my descriptors file
package com.primavera.flex.admin.calendar.ui
import com.adobe.cairngorm.control.CairngormEventDispatcher;
import
com.primavera.flex.admin.calendar.events.GetProjectEvent;
import com.primavera.flex.admin.calendar.vo.ProjwbsVO;
import mx.collections.ArrayCollection;
import mx.collections.ICollectionView;
import mx.controls.treeClasses.DefaultDataDescriptor;
import mx.events.CollectionEvent;
import mx.events.CollectionEventKind;
public class PickListTreeDescriptor extends
DefaultDataDescriptor
public function PickListTreeDescriptor()
super();
override public function getData(node:Object,
model:Object=null):Object
return node;
override public function hasChildren(node:Object,
model:Object=null):Boolean
return ProjwbsVO(node).isEPS();
override public function isBranch(node:Object,
model:Object=null):Boolean
return ProjwbsVO(node).isEPS();
//return false;
override public function getChildren(node:Object,
model:Object=null):ICollectionView
var epsVO : ProjwbsVO = ProjwbsVO(node);
if (epsVO.isEPS())
// this check for delay loading once the data is loaded it
should not make a remote call again
if(epsVO.isProjectsLoaded == false)
epsVO.isProjectsLoaded = true;
var projectEvent : GetProjectEvent = new
GetProjectEvent(null);
projectEvent.projwbsVO = epsVO;
CairngormEventDispatcher.getInstance().dispatchEvent(projectEvent);
var collection:ICollectionView = ICollectionView(model);
var event:CollectionEvent = new
CollectionEvent(CollectionEvent.COLLECTION_CHANGE);
event.kind = CollectionEventKind.ADD;
event.items = ArrayCollection(epsVO.children).toArray();
collection.dispatchEvent(new
CollectionEvent(CollectionEvent.COLLECTION_CHANGE));
return epsVO.children;
Projwbs is my object in Arraycollection. Hierachy is like EPS
can have projects(leafnode) and child Eps(branch node). EPS is
determined if projwbs.isEps returns true.
On UI it gives a single root node in a collapsed state. When
i expand it furthur it gives child EPS and projects in it. On
expanding root node i get childrens but in screen Vscrollbar is not
visible.
Please let me know if you have any thougts on this.