如何在QtreeView中立即显示添加的节点？

Question

当我展开节点时，everythig效果很好：

void DTree::expand(const QModelIndex & index){
  if (treeModel->hasChildren(index)) return;
  DNode &node = *static_cast<DNode*>(index.internalPointer());
  qint32 size = node.makeChildren();
  treeModel->beginInsertRows(index, 0, size);
  treeModel->endInsertRows();
  setExpanded(index, true);
}

但是当我尝试在其方法中显示节点时，它失败了：

qint64 DNode::ins(){
.... some code of adding to database a new node
// here I try to make node show. ord() - new node's order in DB which starts with 1
  treeModel->beginInsertRows(treeModel->createIndex(parent->ord() - 1, 0,
    parent), ord() - 1, ord() - 1);
  treeModel->endInsertRows();
........  
}

我试图使用QPersistentModelIndex - 徒劳无功。 提前谢谢！