Attach a CSS or JS library to a View in Drupal 8

mymodule.libraries.yml

custom_view:
  css:
    component:
      css/custom_view.css: {}

mymodule.module

<?php 
/**
 * Implements hook_views_pre_render().
 */
function custom_views_pre_render(ViewExecutable $view) {
  if (isset($view) && ($view->storage->id() == 'my_view')) {
    $view->element['#attached']['library'][] = 'custom/custom_view';
  }
}

$view->id() returns the view id, without having to access the content storage.

this works for me

function MODULENAME_views_pre_render(\Drupal\views\ViewExecutable $view) {
}

you can check this module "https://www.drupal.org/project/views_attach_library" to attach CSS or JS library to a View in Drupal 8

I understand that custom_view is the library name as defined in mymodule.libraries.yml. But where is custom defined in view->element['#attached']['library'][] = 'custom/custom_view'; ? Is that hardcoded? I had the impression it had to be the module name.

@com2 the first part of the library ("custom", here) is the name of the module or theme which provides the library. So for the example above, it should be mymodule/custom_view