Can't remove a node from a tree

Question

I am using the custom tree dataDescriptor provided in Flex live
doc. It works for creating the tree and add notes, however when I
try to remove a node from the tree it cant work. Does anyone have
any idea?
This is the code for MyCustomeTreeDataDescriptor.as
package
import mx.collections.ArrayCollection;
import mx.collections.CursorBookmark;
import mx.collections.ICollectionView;
import mx.collections.IViewCursor;
import mx.events.CollectionEvent;
import mx.events.CollectionEventKind;
import mx.controls.treeClasses.*;
public class MyCustomTreeDataDescriptor implements
ITreeDataDescriptor
// The getChildren method requires the node to be an Object
// with a children field.
// If the field contains an ArrayCollection, it returns the
field
// Otherwise, it wraps the field in an ArrayCollection.
public function getChildren(node:Object,
model:Object=null):ICollectionView
try
if (node is Object) {
if(node.children is ArrayCollection){
return node.children;
}else{
return new ArrayCollection(node.children);
catch (e:Error) {
trace("[Descriptor] exception checking for getChildren");
return null;
// The isBranch method simply returns true if the node is an
// Object with a children field.
// It does not support empty branches, but does support null
children
// fields.
public function isBranch(node:Object,
model:Object=null):Boolean {
try {
if (node is Object) {
if (node.children != null) {
return true;
catch (e:Error) {
trace("[Descriptor] exception checking for isBranch");
return false;
// The hasChildren method Returns true if the node actually
has children.
public function hasChildren(node:Object,
model:Object=null):Boolean {
if (node == null)
return false;
var children:ICollectionView = getChildren(node, model);
try {
if (children.length > 0)
return true;
catch (e:Error) {
return false;
// The getData method simply returns the node as an Object.
public function getData(node:Object,
model:Object=null):Object {
try {
return node;
catch (e:Error) {
return null;
// The addChildAt method does the following:
// If the parent parameter is null or undefined, inserts
// the child parameter as the first child of the model
parameter.
// If the parent parameter is an Object and has a children
field,
// adds the child parameter to it at the index parameter
location.
// It does not add a child to a terminal node if it does not
have
// a children field.
public function addChildAt(parent:Object, child:Object,
index:int,
model:Object=null):Boolean {
var event:CollectionEvent = new
CollectionEvent(CollectionEvent.COLLECTION_CHANGE);
event.kind = CollectionEventKind.ADD;
event.items = [child];
event.location = index;
if (!parent) {
var iterator:IViewCursor = model.createCursor();
iterator.seek(CursorBookmark.FIRST, index);
iterator.insert(child);
else if (parent is Object) {
if (parent.children != null) {
if(parent.children is ArrayCollection) {
parent.children.addItemAt(child, index);
if (model){
model.dispatchEvent(event);
model.itemUpdated(parent);
return true;
else {
parent.children.splice(index, 0, child);
if (model)
model.dispatchEvent(event);
return true;
return false;
// The removeChildAt method does the following:
// If the parent parameter is null or undefined, removes
// the child at the specified index in the model.
// If the parent parameter is an Object and has a children
field,
// removes the child at the index parameter location in the
parent.
public function removeChildAt(parent:Object, child:Object,
index:int, model:Object=null):Boolean
var event:CollectionEvent = new
CollectionEvent(CollectionEvent.COLLECTION_CHANGE);
event.kind = CollectionEventKind.REMOVE;
event.items = [child];
event.location = index;
//handle top level where there is no parent
if (!parent)
var iterator:IViewCursor = model.createCursor();
iterator.seek(CursorBookmark.FIRST, index);
iterator.remove();
if (model)
model.dispatchEvent(event);
return true;
else if (parent is Object)
if (parent.children != undefined)
parent.children.splice(index, 1);
if (model)
model.dispatchEvent(event);
return true;
return false;
This is my tree definition:
<mx:Tree width="143" top="0" bottom="0" left="0"
height="100%"
id="publicCaseTree"
dataDescriptor="{new MyCustomTreeDataDescriptor()}"
dataProvider="{ac}"
defaultLeafIcon="@Embed('assets/caseIcon.png')"
change="publicTreeChanged(event)"
dragEnabled="true"
dragMoveEnabled="false"/>
This is how I remove the selected node from the tree. When
Delete button is clicked, the doDeleteCase function is
exectuted.
public function publicTreeChanged(event:Event):void {
selectedNode =
publicCaseTree.dataDescriptor.getData(Tree(event.target).selectedItem,
ac);
public function doDeleteCase(event:Event):void{
publicCaseTree.dataDescriptor.removeChildAt(publicCaseTree.firstVisibleItem,
selectedNode, 0, ac);
Any help would be appreciated.Thanks.

Answer 1

Finally I removed nodes from tree, but not sure I did in the
right way. Anybody encounter the same problem, please
discuss.