Render block programmatically in Drupal 8 returns 0

Question

I create a block at /admin/structure/block/block-content and I want programmatically render it in our custom template files. What I did is

function hook_preprocess_page(&$vars) {

    $block = \Drupal\block_content\Entity\BlockContent::load(2);
    $vars['contact-us-info-block']= \Drupal::entityTypeManager()->getViewBuilder('block_content')->view($block);
    //kint( ($vars['contact-us-info-block']));
    //kint( drupal_render($vars['contact-us-info-block']));
}

and in page template file I try

<p>{{ contact-us-info-block }} </p>

but I only see a "0" in output.

if I use

$vars['contact-us-info-block'] = drupal_render($vars['contact-us-info-block']);

everything is Ok but I find out drupal_render is deprecated in Drupal 8. Where is problem and how can I render a block at page template programmatically?

Answer 1

For display only your block in your templates with preprocess the best way is

$block = Block::load('my_block_id');
$variables['My_region'] = \Drupal::entityManager()
      ->getViewBuilder('block')
      ->view($block);

And in your page.html.twig or node.html.twig or xxx.html.twig use your variable My_region like this :

{% if page.My_region %}
    {{ page.My_region }}
{% endif %}

And in rendable array (custom module) by exemple into an controller custom in content():

public function content() {
    $block = Block::load('my_block_id');
    $block_content = \Drupal::entityManager()
      ->getViewBuilder('block')
      ->view($block);

          return array(
            '#type' => 'container',
            '#attributes' => array(
            'class' => array("Myclass"),
          ),
           "element-content" => $block_content,
           '#weight' => 0,
  );
}

drupal_render is not usefull drupal already assume the render in D8 and this is deprecated (https://api.drupal.org/api/drupal/core!includes!common.inc/function/drupal_render/8)

it's a bit heavy, it is better to use the maximum area system and does not add load block from the preprocess. In the case of using a controller in your modules this seems a justified use.

Answer 2

Attentively see topic: https://drupaldeveloper.in/codelet/drupal8-set-block-region-programmatically

You add and display block correctly but have some mistakes in your code.

The first mistake when you load block:

$block = \Drupal\block_content\Entity\BlockContent::load(2);

Do you have block with id "2"? As I understand you have block with id "block_content" and you need load this block.

After that you need add block to variables and you did, but make mistake in method getViewBuilder() you must set 'block', not 'block_content'.

Also, you don't need to use drupal_render. So the final correct code must be next:

function hook_preprocess_page(&$vars) {

    $block = \Drupal\block_content\Entity\BlockContent::load('block_content');
    $vars['contact-us-info-block']= \Drupal::entityTypeManager()->getViewBuilder('block')->view($block);
}

Answer 3

function hook_preprocess_page(&$vars) {
  $block = \Drupal\block_content\Entity\BlockContent::load(2);
  $blockview = \Drupal::entityTypeManager()->getViewBuilder('block_content')->view($block);
  $vars['contact-us-info-block'] = render($blockview);
}