Symfony form not shown in template - symfony

Question

In a Symfony 3.4 project, I just created a new form type ProductSearchType. The form fields are not shown in twig template. There are only the <form> tags, but nothing between them.
FormType:
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('name', TextType::class, [
'required' => false,
'label' => 'Name',
])
->add('sizes', EntityType::class, [
'required' => false,
'label' => 'Bauform',
'class' => ProductSize::class,
])
->add('description', TextType::class, [
'required' => false,
'label' => 'Beschreibung',
])
->add('price', EntityType::class, [
'required' => false,
'label' => 'Preiskategorie',
'class' => ProductPrice::class,
])
->add('booster', EntityType::class, [
'required' => false,
'label' => 'Hörverlust',
'class' => ProductBooster::class,
])
->add('brand', EntityType::class, [
'required' => false,
'label' => 'Marke',
'class' => ProductBrand::class,
]);
}
Action:
public function index(Request $request): Response
{
$products = $this->getDoctrine()->getRepository(Produkt::class)
->findBy([
'showOnEmptySearch' => true,
], [
'sortOnEmptySearch' => 'asc',
]);
$searchForm = $this->createForm(ProductSearchType::class);
$searchForm->handleRequest($request);
$params = [
'products' => $products,
'search_form' => $searchForm->createView(),
];
return $this->render('Products/index.html.twig', $params);
}
Twig part:
{% block template_filter %}
<h1>
Suche
</h1>
<div class="filter_box">
{{ form(search_form) }}
</div>
{% endblock %}

Answer 1

I recommend to follow the documentation. On your example:
$searchForm = $this->createForm(ProductSearchType::class); should be:
$searchForm = $this->createForm(ProductSearchType::class)->getForm();.
Also on twig;
{{ form_start(search_form) }}
{{ form_widget(search_form) }}
{{ form_end(search_form) }}
Here is the documentation link. Welcome to Stackoverflow.
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