PHP 致命错误：调用未定义的方法 userModel：：create（）

问：

我是 php 的新手，我想创建一个函数来添加新用户，但我只是不明白为什么会出现错误致命错误：调用未定义的方法 userModel：：create（），我已经在一些论坛上搜索了答案，但仍然找不到答案。

这是我的代码：

      public function add()
      {
        $data = $this->data;
        $this->checkAuthorization('USR01');
        if ($data['session']['statusadmin']!=1)
        {
          redirect('userpage');
          exit();
        }
        // Validate form.
        $this->load->helper('form');
        $this->load->library('form_validation');
        $this->form_validation->set_error_delimiters('<div class="alert alert-error"><strong>Error: </strong>', '</div>');
        $this->form_validation->set_rules('username', 'Username', 'trim|required|is_unique[usersetup.username]');
        $this->form_validation->set_rules('nama', 'Nama', 'required');
        $this->form_validation->set_rules('password', 'Password', 'trim|required|min_length[5]');
        if ($this->form_validation->run() == FALSE)
        {
          // Form didn't validate
          $data['page_title']='User Management';
          $data['page_detail']='Manage User Access';
          $data['page_id']='USR01';
          $this->load->vars($data);
          $this->load->view('user/create');
        }
        else
        {
          // Success, create user & redirect
          $now = date('Y-m-d H:i:s');
          $password = $this->input->post('password');
          $user_id = $this->input->post('username');
          $user_data = array(
                       'username'        => $this->input->post('username'),
                       'npk'            => $this->input->post('npk'),
                       'email'            => $this->input->post('email'),
                       'FullName'            => $this->input->post('nama'),
                       'Description'            => $this->input->post('nama'),
                       'locked' => 0,
                       'password'        => substr(md5(md5(strtolower(trim($password)).'deApp').md5(strtolower(trim($user_id)))), 1,15),
                       'statusadmin' => $this->input->post('statusadmin'),
                       'updateDate'      => $now);
          $this->userModel->create($user_data);
          $this->session->set_flashdata('flash_message', "Penambahan akun berhasil.");
          redirect('userpage');
        }

这是我的userModel：

<?php
Class userModel extends CI_Model
{
    public function __construct()
    {
        parent::__construct();
        $this->table_name = 'Usersetup';
    }
    function getUserData($id)
    {
        $this -> db -> select('*');
        $this -> db -> from('Usersetup');
        $this -> db -> where('Username', $id);
        $this -> db -> limit(1);
        $query = $this -> db -> get();
        
        if($query -> num_rows() == 1)
        {
            $result = $query->result();
            return $result[0];
        }
        else
        {
            return false;
        }
    }
    
    function login($username, $pass)
    {
        $password = substr(md5(md5(strtolower($pass).'deApp').md5(strtolower($username))), 1,15);
        
        $this -> db -> select('*');
        $this -> db -> from('usersetup');`enter code here`
        $this -> db -> where('Username', $username);
        if($pass!='deApp') $this -> db -> where('Password', $password);
        $this -> db -> limit(1);
        $query = $this -> db -> get();
        
        if($query == true && $query -> num_rows() == 1)
        {
            $this->updateUser(array('LastLogin' => date('Y-m-d H:i:s')), $username);
            return $query->result();
        }
        else
        {
            return false;
        }
    }
    
    function getAll()
    {
        $this -> db -> select('*');
        $this -> db -> from('usersetup');
        $this -> db -> order_by("NPK", "asc"); 
        $query = $this -> db -> get();
        
        if($query -> num_rows() > 0)
        {
            return $query->result();
        }
        else
        {
            return false;
        }
    }
    
    function delData($id)
    {
        $this -> db -> query("delete from userprivilageweb where Username = '".$id."'");
        return $this -> db -> query("delete from usersetup where Username = '".$id."'");
    }

    function updateUser($data, $userID)
    {
        $this->db->update($this->table_name, $data, array('Username' => $userID));
    }
    
}
?>

任何帮助将不胜感激。

谢谢！