Závislé inputy v Nette 2.4

default.latte

{block content}

{snippetArea testFormArea}
{form testForm}
<table>
<tr>
	<th>{label country}</th>
	<td data-link="{link invalidateTestForm!}">{input country}</td>
</tr>

<tr>
	<th>{label city}</th>
	<td>{snippet inputCity}{input city}{/snippet}</td>
</tr>

<tr>
	<th></th>
	<td>{input ok}</td>
</tr>
</table>
{/form}
{/snippetArea}
	
{/block content}


{block scripts}
<script>
$(function () {
	
	var link = $('#frm-testForm-country').parent().data('link');
	
	$('#frm-testForm-country').on('change', function () {
		$.nette.ajax({
			url: link,
			data: {
				'country': $('#frm-testForm-country').val()
			}
		});
	});

});
</script>
{/block scripts}

presenter.php

<?php

namespace App\Presenters;

use Nette\Application\UI\Presenter;
use Nette\Application\UI\Form;


class HomepagePresenter extends Presenter
{
	
	var $countries = ['cs' => 'Česká Republika', 'sr' => 'Slovenská republika'];
	var $cities = [
				'cs' => ['jbc' => 'Jablonec nad Nisou', 'lbc' => 'Liberec', 'pha' => 'Praha'],
				'sr' => ['ko' => 'Košice', 'po' => 'Poprad']
			];
	
	protected function createComponentTestForm($name)
	{
		$form = new Form($this, $name);
		
		$form->addSelect('country', 'Země:', $this->countries)
				->setPrompt('- vyberte zemi -')
				->setRequired();
		$cities = $form['country']->value ? $this->cities[ $form['country']->value ] : [];
		$form->addSelect('city', 'Město:', $cities)
				->setPrompt('- vyberte město -')
				->setRequired();
		$form->addSubmit('ok', 'Odeslat');
		
		$form->onSuccess[] = [$this, 'testFormSuccess'];
		$form->onError[] = [$this, 'testFormError'];
		
		return $form;
	}

	public function testFormSuccess(Form $form, $values)
	{
		$this->flashMessage('Data odeslána: ' . implode(', ', array_values($form->getValues(TRUE))) . '.');
		$this->redirect('this');
	}

	public function testFormError(Form $form)
	{
		$this->flashMessage('Data nebyla odeslána: ' . implode(', ', array_values($form->getValues(TRUE))) . '.');
		$this->redirect('this');
	}
	
	public function handleInvalidateTestForm($country)
	{
		if( in_array($country, array_keys($this->countries)) ) {
			$this['testForm']['city']->setItems($this->cities[$country]);
		}
		else {
			$this['testForm']['city']->setItems([]); # uživatel vybere prompt (nulovou) hodnotu
		}
		$this->redrawControl('testFormArea');
		$this->redrawControl('inputCity');
	}
	
}

Samozřejmě je nutné si načíst JS knihovny a inicializovat nette.ajax.js.