求easyui 的tree 找不到ID··

<script type="text/javascript">    

        $(document).ready(function () {

             mytree = $('#treeDemo').tree({

              AllowDrop: true,

                animate: true,

                dnd: true,

                enableDnd : true,

                checkbox: false,

                url: '/bm/GetListData',

                 onClick: function (node) {

                   

                        if (node.state == "closed")

                            ExpandNode(node);

                        else

                        { CollapseNode(node); }

                } ,

                onContextMenu: function (e, node) {

                    e.preventDefault();

                    $(this).tree('select', node.target);

                    $('#mm').menu('show', {

                        left: e.pageX,

                        top: e.pageY

                    });

                }

            });



        });

 用自带的属性方法mytree.tree("getSelected") 得不到数据
mytree.tree("getSelected").id 总是为空