Prado\Web\UI\ActiveControls\TActiveListControlAdapter::clearSelection PHP Метод

    public function clearSelection()
    {
        if ($this->canUpdateClientSide()) {
            $this->updateListItems();
            if ($this->getControl() instanceof TActiveDropDownList) {
                // clearing a TActiveDropDownList's selection actually doesn't select the first item;
                // we mimic the postback behaviour selecting it (Issue #368)
                $this->getPage()->getCallbackClient()->select($this->getControl(), 'Index', 0);
            } else {
                $this->getPage()->getCallbackClient()->select($this->getControl(), 'Clear');
            }
        }
    }