take a look at my TreeDefinitions
<?xmlversion="1.0"encoding="UTF-8"?><ElementStructurexmlns="http://www.composite.net/ns/management/trees/treemarkup/1.0"xmlns:f="http://www.composite.net/ns/function/1.0"><ElementStructure.AllowedAttachmentsApplicationName="新闻"><DataTypeType="Composite.Data.Types.IPage"/></ElementStructure.AllowedAttachments><ElementRoot><Actions><MessageBoxActionLabel="GUID"MessageBoxTitle="${C1:Data:Composite.Data.Types.IPage:Title}"MessageBoxMessage="${C1:Data:Composite.Data.Types.IPage:Id}"/></Actions><Children><ElementLabel="新闻"Id="ArticleRoot"><Actions><AddDataActionLabel="添加新闻"Type="XjfCms.Data.Types.Article"/></Actions><Children><DataFolderElementsType="XjfCms.Data.Types.Article"DateFormat="yyyy年MM月"FieldGroupingName="PublishDate"Display="Compact"><Actions><AddDataActionLabel="添加新闻"Type="XjfCms.Data.Types.Article"/></Actions><Children><DataFolderElementsDateFormat="dd日"FieldGroupingName="PublishDate"Display="Compact"><Actions><AddDataActionLabel="添加新闻"Type="XjfCms.Data.Types.Article"/></Actions><Children><DataElementsType="XjfCms.Data.Types.Article"Label="${C1:Data:XjfCms.Data.Types.Article:Title}"Display="Auto"><Actions><EditDataActionLabel="编辑新闻"/><DeleteDataActionLabel="删除新闻"/></Actions><Filters><ParentIdFilterParentType="Composite.Data.Types.IPage"ReferenceFieldName="PageId"/></Filters><OrderBy><FieldFieldName="PublishDate"Direction="descending"></Field></OrderBy></DataElements></Children></DataFolderElements></Children></DataFolderElements></Children></Element></Children></ElementRoot></ElementStructure>