AdvancedDataGrid initial column sort

I have an AdvancedDataGrid with mx:HierarchicalData as DataProvider. I need the grid to bi sorted on the second column initially but can't find any way to specify this. Even if I sort the collection befor setting it into the mx:HierarchicalData only the first level remains sorted, while all the child records ge开发者_JAVA技巧t randomized. How to solve this?

---

Use a HierarchicalCollectionView as dataprovider and sort it.

[Bindable]
private var hierarchicalView:IHierarchicalCollectionView;

private function createHierarchicalView():void
{
    hierarchicalView = new HierarchicalCollectionView(hierarchicalData);
    hierarchicalView.sort = new Sort();
    hierarchicalView.sort.fields = [new SortField('field2') /* add additional fields if needed */];
    hierarchicalView.refresh();
}

<mx:AdvancedDataGrid designViewDataType="tree" dataProvider="{hierarchicalView}">