Yii mPDF css错误

我读过一些关于如何在mPDF中添加css样式的帖子，我正在使用Yii框架，我尝试了很多方法，但都没有结果，关于如何使其工作有什么想法

$this->layout="//layouts/pdf";
        $mPDF = Yii::app()->ePdf->mpdf();
        $html = $this->render('pdf', array('dataProvider'=>$dataProvider), true);

        $stylesheet = file_get_contents(Yii::app()->request->baseUrl.'/css/print.css');
        $stylesheet .= file_get_contents(Yii::app()->request->baseUrl.'/css/main.css');

        $mPDF->WriteHTML($stylesheet, 1);
        $mPDF->WriteHTML($html, 2);

        $mPDF->Output('Inmuebles',EYiiPdf::OUTPUT_TO_BROWSER);

这是控制器代码

<link rel="stylesheet" type="text/css" href="<?php echo Yii::app()->request->baseUrl; ?>/css/print.css" media="print" />
    <link rel="stylesheet" type="text/css" href="<?php echo Yii::app()->request->baseUrl; ?>/css/main.css" />

---

在控制器中尝试这种方式，它对我有效：

$mPDF = Yii::app()->ePdf->mpdf();
$html = $this->render('pdf', array('dataProvider'=>$dataProvider), true);

$stylesheet = file_get_contents(/* path to first css file */);
$stylesheet .= file_get_contents(/* path to second css file */);

$mPDF->WriteHTML($stylesheet, 1);
$mPDF->WriteHTML($html, 2);

echo $mPDF->Output('Inmuebles',EYiiPdf::OUTPUT_TO_BROWSER);

---

文件\u get\u contents/yii/yiitest/css/print.css:无法打开流：没有这样的文件或目录，但文件以如下方式存在：文件\u get\u contentsYii:：GetPathFalias'webroot'/*从项目根目录到css文件的路径*/因为webroot是项目根目录的实际路径。$stylesheet=file\u get\u contentsDIR./../css/print.css'；$stylesheet.=file_get_contentsDIR'/../css/main.css'；我就是这样修好的，但是非常感谢！

$mPDF = Yii::app()->ePdf->mpdf();
$html = $this->render('pdf', array('dataProvider'=>$dataProvider), true);

$stylesheet = file_get_contents(/* path to first css file */);
$stylesheet .= file_get_contents(/* path to second css file */);

$mPDF->WriteHTML($stylesheet, 1);
$mPDF->WriteHTML($html, 2);

echo $mPDF->Output('Inmuebles',EYiiPdf::OUTPUT_TO_BROWSER);