The table is not displayed

Question

I have a Basic Component class. Other classes are imposed on him. All functions I implement in class followers. There are children in these classes In my window, I implement the table and in this table I have to write the children of different classes. such as Tsategory's class and he has children. I need to write these children in the table. but when I do it on a date I do not show anything ((

int TableModel::rowCount(const QModelIndex& /*parent*/) const
{
    return (int)mCompositeComponent->numChildren();
}

int TableModel::columnCount(const QModelIndex& /*parent*/) const
{
   return 3;
}

QVariant TableModel::data(const QModelIndex& index, int role) const
{
    int row = index.row();
    int col = index.column();

    if (role == Qt::DisplayRole)
    {
       const Component* component = mCompositeComponent->child(row);
       if (component != nullptr)
            return QString(component->name());
    }
    return QVariant();
}