PHP致命错误 - 类＆＃39; Html＆＃39;未找到

Question

我正在制作一个演示网站http://www.yiichina.com/doc/guide/2.0/start-forms。我看到了致命的错误。

PHP代码：

＆＃13;

＆＃13;

<?php
use yii\helpers\Html;
?>
<p>You have entered the following information:</p>
<ul>
    <li><lable>Name</lable>:<?=Html::encode($model->name) ?></li>
    <li><lable>Email</lable>:<?=Html::encode($model->email) ?></li>
</ul>

＆＃13;

＆＃13;

＆＃13;

致命错误：

<--
PHP Fatal Error – yii\base\ErrorException
Class 'Html' not found
1. in C:\Apache24\htdocs\yii\basic\views\site\entry-confirm.php at line 6
123456789

2. yii\base\ErrorHandler::handleFatalError()
Yii Framework
2016-03-06, 04:43:36

Apache/2.4.18 (Win64) OpenSSL/1.0.2f PHP/5.6.18
Yii Framework/2.0.7
-->