//! [9] QModelIndex DomModel::parent(const QModelIndex &child) const { if (!child.isValid()) return QModelIndex(); DomItem *childItem = static_cast<DomItem*>(child.internalPointer()); DomItem *parentItem = childItem->parent(); if (!parentItem || parentItem == rootItem) return QModelIndex(); return createIndex(parentItem->row(), 0, parentItem); }