Prado\Web\UI\WebControls\TDataGridColumnCollection::insertAt PHP Method

    public function insertAt($index, $item)
    {
        if ($item instanceof TDataGridColumn) {
            $item->setOwner($this->_o);
            parent::insertAt($index, $item);
        } else {
            throw new TInvalidDataTypeException('datagridcolumncollection_datagridcolumn_required');
        }
    }