DevExpress.XtraTreeList.TreeList 显示行号

private void treeListDsh_CustomDrawNodeIndicator(object sender, DevExpress.XtraTreeList.CustomDrawNodeIndicatorEventArgs e)
        {
            DevExpress.XtraTreeList.TreeList tmpTree = sender as DevExpress.XtraTreeList.TreeList;
            DevExpress.Utils.Drawing.IndicatorObjectInfoArgs args = e.ObjectArgs as DevExpress.Utils.Drawing.IndicatorObjectInfoArgs;
            if (args != null)
            {
                int rowNum = tmpTree.GetVisibleIndexByNode(e.Node) + 1;
                args.DisplayText = rowNum.ToString();
            }
            e.ImageIndex = -1;
        }