Question

I have an AdvancedDataGrid (ADG) with a HierarchicalData dataProvider:

<mx:AdvancedDataGrid xmlns:mx='http://www.adobe.com/2006/mxml'     dataProvider='{__model.myHierarchicalData}'      displayItemsExpanded='true' sortExpertMode='true' dropEnabled='true'      sortableColumns='false' draggableColumns='false'      resizableColumns='true' textAlign='left' defaultLeafIcon='{null}'      folderOpenIcon='{null}' folderClosedIcon='{null}'/> 

When I initially set the HierarchicalData instance in the Model, it is displayed as expected:

function buildHierarchicalData(parentItems:ArrayCollection):void {     __model.myHierarchicalData = new HierarchicalData();      __model.myHierarchicalData.source = parentItems; } 

parentItems is a Collection of ParentItem valueObjects:

package {     [Bindable]     public class ParentItem     {         public var children:ArrayCollection;          public var label:String;     } } 

However, when I move child items from one parent to another (via drag-and-drop), the update is not visible, using this code:

function moveChildren(movedChildren:Array /* of ParentItem */):void {     parentItem.children = new ArrayCollection(movedChildren); } 

For some reason, however, this DOES work:

function moveChildren(movedChildren:Array /* of ParentItem */):void {     parentItem.children.source = movedChildren; } 

Why do I have to update the source of the ArrayCollection???

Answer 1

Thanks to dirkgently for directing me to the answer. I am now eliminating the need for a HierarchicalData property in my model, and instead setting the Hierarchical dataProvider right in the MXML:

<mx:AdvancedDataGrid xmlns:mx='http://www.adobe.com/2006/mxml'>     <mx:dataProvider>         <mx:HierarchicalData source='{__model.parentItems}' />     </mx:dataProvider> </mx:AdvancedDataGrid>