初始化后，PHP类属性为NULL

Question

我这里有问题， 当我上这堂课的时候 类属性即使在初始化后仍为NULL

class User
{
    public $name;
    public $id;
    public $email;
    private $password;

    private $dbconn;
    function __construct()
    {
        $this->dbconn= new Config\Database();
    }
    public function login( $email, $password){
        $matches=$this->dbconn->query("SELECT pwhash from users WHERE email = '$email'");
        if($matches->num_rows==0){
            return "no such user";
        }else{
            while($row =$matches->fetch_assoc()){
                if($row['pwhash']==hash("sha256",$password)){
                $this->name=$row['name'];
                $this->id=$row['id'];

                return "login successful";
            }else{
                return "login fail";
            }
        }
    }
}

我尝试访问php文件之外的类，

$user = new User\User();
if(isset($_POST['email']) && isset($_POST['password']) ){
    $loginmessage=$user->login($_POST['email'],$_POST['password']);
}
if($loginmessage=="login successful"){
        $userarray= get_object_vars($user);
        var_dump($userarray);

}

然后我显示

的var_dump $userarray

["name"]=>
  NULL
  ["id"]=>
  NULL

背后的原因是什么？

Answer 1

您没有选择＆＃39; name＆＃39;或者＆＃39; id＆＃39;在你的SQL中，所以你在使用时得到NULL：

$this->name=$row['name'];
$this->id=$row['id'];

将您的SQL更改为：

$matches=$this->dbconn->query("SELECT pwhash,name,id from users WHERE email = '$email'");