Flex中如何通过给openItems属性，设置一个XMLList或Array对象来打开Tree的一个节点

main.mxml

1. <?xml version="1.0" encoding="utf-8"?>
2. <mx:Applicationxmlns:mx="http://www.adobe.com/2006/mxml"
3. layout="vertical"
4. verticalAlign="middle"
5. backgroundColor="white">
7. <mx:Script>
8. <![CDATA[
9. private function openAllNodes():void {
10. tree.openItems = dp..node;
11. }
13. private function closeAllNodes():void {
14. tree.openItems = [];
15. }
16. ]]>
17. </mx:Script>
19. <mx:XMLid="dp">
20. <root>
21. <nodelabel="Parent 1">
22. <nodelabel="Child 1" />
23. <nodelabel="Child 2">
24. <nodelabel="Grandchild 1" />
25. <nodelabel="Grandchild 2" />
26. </node>
27. <nodelabel="Child 3" />
28. <nodelabel="Child 4" />
29. </node>
30. </root>
31. </mx:XML>
33. <mx:ApplicationControlBardock="true">
34. <mx:Buttonlabel="Open all nodes" click="openAllNodes();" />
35. <mx:Buttonlabel="Close all nodes" click="closeAllNodes();" />
36. </mx:ApplicationControlBar>
38. <mx:Treeid="tree"
39. dataProvider="{dp}"
40. showRoot="false"
41. labelField="@label"
42. width="200"/>
44. </mx:Application>