php - 为 foreach() 提供的 undefined variable 和无效参数

Question

我正在尝试学习 codeigniter，但我遇到了问题。在 View 中为 foreach() 提供了一个错误 Undefined variable 和 Invalid argument。这是代码:

模型(Model_Users.php):

class Model_users extends CI_Model {

    function __construct() {
        parent::__construct();
    }

    function getFirstNames(){
        $query = $this->db->query('SELECT firstname FROM users');

        if($query->num_rows() > 0) {
            return $query->result();
        } else {
            return NULL;
        }
    }

    function getUsers(){

        $query = $this->db->query('SELECT * FROM users');

        if ($query->num_rows() > 0) {
            return $query->result();
        } else {
            return NULL;
        }
    }
}

Controller (welcome.php):

class Welcome extends CI_Controller {

    public function index()
    {
        $this->home();
    }

    public function home()
    {
        $this->load->model('model_users');

        $data['title'] = 'MVC Cool Title';
        $data['page_header']='Intro to MVC Design';
        $data['firstnames'] = $this->model_users->getFirstNames();

        $data['users'] = $this->model_users->getUsers();

        $this->load->view('welcome_message',$data);
    }
}

查看(Welcome_message.php):

<div id="container">
    <h1><?php echo $page_header ?></h1>

    <div id="body">
        <?php
            foreach ($firstnames as $object) {
                echo $object->firstname .'<br/>';
            }
            echo '<br/><hr/><br/>';

            foreach ($users as $object){
                echo $object->firstname . '\'s email address is'. $object->email . '<br/>';
            }
        ?>
    </div>

    <p class="footer">Page rendered in <strong>{elapsed_time}</strong> seconds</p>
</div>

请帮我看看我的代码有什么问题吗？

Answer 1

首先检查值是否返回任何值或不在 Controller 中写入此代码使用

var_dump($firstnames);和var_dump($users);

我认为模型没有返回数据检查表中的任何数据谢谢