遇到一个PHP错误"；未定义变量已定义"；但仍然不起作用

我收到一个错误：

A PHP Error was encountered

Severity: Notice

Message: Undefined variable: data

Filename: controllers/c_verifylogin.php

Line Number: 17

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class C_verifyLogin extends CI_Controller {
    function __construct() {
        parent::__construct();
        //load session and connect to database
        $this->load->model('m_login','login',TRUE);
        $this->load->helper(array('form', 'url','html'));
        $this->load->library(array('form_validation','session'));
    }

    function index() {
        $this->form_validation->set_rules('studentid', 'studentid', 'trim|required|xss_clean');
        $this->form_validation->set_rules('password', 'password', 'trim|required|xss_clean|callback_check_database');

        if($this->form_validation->run() == FALSE) {
            $this->load->view('v_login');
            } else {
                //Go to private area
                redirect(base_url('c_home'), 'refresh');
            }       
     }

     function check_database($password) {
         //Field validation succeeded.  Validate against database
         $studentid = $this->input->post('studentid');
         //query the database
         $result = $this->login->login($studentid, $password);
         if($result) {
             $sess_array = array();
             foreach($result as $row) {
                 //create the session
                 $sess_array = array('studentid' => $row->studentid);
                 //set session with value from database
                 $this->session->set_userdata('logged_in', $sess_array);
                 }
          return TRUE;
          } else {
              //if form validate false
              $this->form_validation->set_message('check_database', 'Invalid username or password');
              return FALSE;
          }
      }
}
/* End of file c_verifylogin.php */
/* Location: ./application/controllers/c_verifylogin.php */

这是有错误的文件名：

A PHP Error was encountered

Severity: Notice

Message: Undefined variable: data

Filename: controllers/c_verifylogin.php

Line Number: 17

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class C_verifyLogin extends CI_Controller {
    function __construct() {
        parent::__construct();
        //load session and connect to database
        $this->load->model('m_login','login',TRUE);
        $this->load->helper(array('form', 'url','html'));
        $this->load->library(array('form_validation','session'));
    }

    function index() {
        $this->form_validation->set_rules('studentid', 'studentid', 'trim|required|xss_clean');
        $this->form_validation->set_rules('password', 'password', 'trim|required|xss_clean|callback_check_database');

        if($this->form_validation->run() == FALSE) {
            $this->load->view('v_login');
            } else {
                //Go to private area
                redirect(base_url('c_home'), 'refresh');
            }       
     }

     function check_database($password) {
         //Field validation succeeded.  Validate against database
         $studentid = $this->input->post('studentid');
         //query the database
         $result = $this->login->login($studentid, $password);
         if($result) {
             $sess_array = array();
             foreach($result as $row) {
                 //create the session
                 $sess_array = array('studentid' => $row->studentid);
                 //set session with value from database
                 $this->session->set_userdata('logged_in', $sess_array);
                 }
          return TRUE;
          } else {
              //if form validate false
              $this->form_validation->set_message('check_database', 'Invalid username or password');
              return FALSE;
          }
      }
}
/* End of file c_verifylogin.php */
/* Location: ./application/controllers/c_verifylogin.php */

---

我已经寻找这个问题好几个小时了，但我仍然不知道它出了什么问题。有人能帮忙吗？

$data变量未在此处定义。请使用的某个值定义它，如果要传递，则不传递 $data以查看呼叫

    if($this->form_validation->run() == FALSE) {
        $this->load->view('v_login',$data);
        } else {
            //Go to private area
            redirect(base_url('c_home'), 'refresh');
        }       
 }

---

您必须定义

$data

 $data = array('something');
 $this->load->view('v_login',$data);

$this->load->view('v_login');

或

删除

$data

 $data = array('something');
 $this->load->view('v_login',$data);

$this->load->view('v_login');

---

在您的代码中，这里清楚地表明您没有定义$data变量。
因此，您有两个选项：将

$data

定义为类似数组的

$data = array(); 

或者只加载视图而不传递任何变量，如

$this->load->view('v_login');

---

我希望它能帮助您。

确保在

$this->load->view（'v_login'，$data）行之前定义了
$data
。只是
var_dump（$data）；模具（）要查看它包含的内容，$data在哪里定义？它清楚地表明它不是定义的，所以只需定义它并解决问题。这肯定会帮助您将来解决此类问题。