让UniDBTreeGrid默认展开一级节点：

function store.nodeappend(sender, node, index, eOpts)
{
   if (node.raw.depth==1) {
      node.expand();
   }
}

原文地址：

http://forums.unigui.com/index.php?/topic/11740-how-to-expand-unidbtreegrid-first-level-nodes-programmatically/&tab=comments#comment-62357