How to get a child of rootIndex() in QTreeView ?

[Anticross]

I want to get all top level items in my tree view to make a loop. I do next:
@QModelIndex root(rootIndex());

int row = 0;

QModelIndex sessionIndex = root.child(row,SessionsTreeModel::eName);

while (sessionIndex.isValid()) {
    sessionIndex = sessionIndex.sibling(row,SessionsTreeModel::eName);
    int id = m_model->data(sessionIndex,Qt::UserRole).toInt();

    if (sessionID == id) {
        m_model->removeSession(sessionIndex.row());
        update();
        return;
    }

    row++;
}@

But my sessionIndex always invalid. I find next in Qt Assistant : bq. QModelIndex QModelIndex::child ( int row, int column ) const

Returns the child of the model index that is stored in the given row and column.

Note: This function does not work for an invalid model index which is often used as the root index. bq.

So how can I get child of rootIndex ?

[ChrisW67]

@
m_model->index(row, column, rootIndex());
@
any good?