if(isset($_POST['pdf']) && $_POST['pdf']=="pdf")
            {
                $this->load->model('voutput_model');
                $final_view = $data['frmReport'];
                $PDF_Name = "report.pdf";
                $this->votput_model->pdf($PDF_Name,$final_view);

            }

我在模型文件中有以下代码

class Voutput_model extends CI_Model{

    public function __construct()
    {
        parent::__construct();
        $this->CI = get_instance();
    }

    public function pdf($file_name,$filecontents){
        $this->pdf_path = $this->config->item('pdf_path');
        $this->load->library('htmltopdf/Html2fpdf');
        $file['Attach_path'] = $this->pdf_path.$file_name;
        $this->html2fpdf->generate_pdf($file['Attach_path'],$filecontents,'Y');
    }
}

当我执行代码时,我收到如下错误：

Severity: Notice
Message: Undefined property: Voutput::$Voutput_model
Filename: controllers/voutput.PHP
Fatal error: Call to a member function pdf() on a non-object in 
            C:\xampp\htdocs\asset\application\controllers\voutput.PHP