Joomla $ this-> get（'Form'）返回NULL

Question

I have a view views/detailedforms/view.html.php

defined('_JEXEC') or die;

jimport('joomla.application.component.view');

class Detailed_formViewDetailedforms extends JViewLegacy {

    protected $items;
    protected $pagination;
    protected $state;
    protected $params;
    protected $form;

/**
 * Display the view
 */
public function display($tpl = null) {
    $app = JFactory::getApplication();

    $this->state = $this->get('State');
    $this->form = $this->get('Form');
    var_dump($this->form);
} 

and model models/forms/detailedforms.xml

<?xml version="1.0" encoding="UTF-8"?>
<form>
<fieldset name="contact" label="Detail_FORM">
    <field name="name"
        type="text"
        id="tailor-made-name"
        size="30"
        description="FORM_NAME_DESC"
        label="FORM_NAME_LABEL"
        filter="string"
        required="true"
    />
    <field name="email"
        type="email"
        id="email"
        size="30"
        description="EMAIL_DESC"
        label="EMAIL_LABEL"
        filter="string"
        validate="tailoremail"
        required="true"
    />

</fieldset>

$this->form returns null. Please help, how to fix the issue. Due to this issue, fatal error occurs in the template file.