Wie stelle ich es an, dass gewisse Inhalte einer Komponente in einer Modalbox angezeigt werden?

Der Inhalt der Modalbox kann zum Beispiel mit einer eigenen Komponenten-View gefüllt werden.
Dazu werden folgende Dateien benötigt:

views/testview/view.raw.php
views/testview/tmpl/modalbox.php

view.raw.php

<?php
 
// No direct access
defined('_JEXEC') or die;
 
use \Joomla\CMS\Factory;
 
/**
 * View class for modals
*/
 
class ComponentViewTestview extends \Joomla\CMS\MVC\View\HtmlView
{
 
  /**
  * Display the view
  *
  * @param   string  $tpl  Template name
  * @return void
  * @throws Exception
  */
  public function display($tpl = null)
  {
     $app = Factory::getApplication();
 
     $this->state = $this->get('State');
     $this->params = $app->getParams('com_component');
 
 
     // Check for errors.
     if (count($errors = $this->get('Errors')))
     {
     throw new Exception(implode("\n", $errors));
     }
 
     $this->_prepareDocument();
     parent::display($tpl);
  }
}

modalbox.php

<?php
// No direct access
defined('_JEXEC') or die;
 
//URL: index.php?option=com_component&view=testview&format=raw&layout=modalbox
?>
 
<p>Inhalt der Modalbox</p>

default.php

<?php
 
use \Joomla\CMS\HTML\HTMLHelper;
use \Joomla\CMS\Router\Route;
 
HTMLHelper::_('behavior.modal');
 
.
.
.
 
<a id ="modalbox1" href="<?php echo Route::_('index.php?option=com_component&view=testview&format=raw&layout=modalbox'); ?>" class="modal">Open Modalbox</a>

default.php

<?php
 
use \Joomla\CMS\HTML\HTMLHelper;
use \Joomla\CMS\Router\Route;
 
.
.
.
 
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#bootstrapModalbox">
  Bootstrap: Modalbox
</button>
 
<!-- Modal-Box -->
<div class="modal hide fade jviewport-width80 in" id="bootstrapModalbox" tabindex="-1" aria-labelledby="bootstrapModalboxTitle" aria-hidden="true">
  <div class="modal-header">
    <button type="button" class="close novalidate" data-dismiss="modal" aria-label="Close">
      <span aria-hidden="true">&times;</span>
    </button>
    <h3 id="bootstrapModalboxTitle">Modalbox title</h3>
  </div>
  <div class="modal-body">
    <iframe class="iframe" src="<?php echo Route::_('index.php?option=com_attlist&view=meldungform&format=raw&layout=modal_success'); ?>" name="iframe name"></iframe>
  </div>
  <div class="modal-footer">
    <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
    <button type="button" class="btn btn-primary">Save changes</button>
  </div>
</div>