方法：判断父对象

connect(ui->treeWidget_nav, &QTreeWidget::itemChanged, [=](QTreeWidgetItem *TWI){
    if (TWI->parent() == TWI_bookmark) {
        qDebug() << TWI->data(0, LOCATION_OF_REAL_PATH).toString() << TWI->text(0);
    }
});
ui->treeWidget_nav->setContextMenuPolicy(Qt::CustomContextMenu);
QMenu *menu_bookmark = new QMenu(ui->treeWidget_nav);
QAction *action_bookmark_rename = new QAction("重命名");
QAction *action_bookmark_move_up = new QAction("上移");
QAction *action_bookmark_move_down = new QAction("下移");
QAction *action_bookmark_delete = new QAction("删除");
menu_bookmark->addAction(action_bookmark_rename);
menu_bookmark->addAction(action_bookmark_move_up);
menu_bookmark->addAction(action_bookmark_move_down);
menu_bookmark->addAction(action_bookmark_delete);
connect(ui->treeWidget_nav, &QTreeWidget::customContextMenuRequested, [=](const QPoint &pos){
    QTreeWidgetItem *TWI = ui->treeWidget_nav->itemAt(pos);
    if (TWI->parent() == TWI_bookmark) {
        menu_bookmark->exec(ui->treeWidget_nav->mapToGlobal(pos));
    }
});
connect(action_bookmark_rename, &QAction::triggered, [=](){
    ui->treeWidget_nav->editItem(ui->treeWidget_nav->currentItem(), 0);
});