PHP登录和注册错误

Question

所示的错误是

"Fatal error: Uncaught Error: Call to a member function query() on string in D:\Users\kukor\Documents\XAMPP\htdocs\timetable\class.ManageUsers.php:22 Stack trace: #0 D:\Users\kukor\Documents\XAMPP\htdocs\timetable\login.php(19): ManageUsers->LoginUsers('kayzmark', 'ultimate') #1 {main} thrown in D:\Users\kukor\Documents\XAMPP\htdocs\timetable\class.ManageUsers.php on line 22"

<?php 
class ManageUsers{ 
    public $link; 

    function __construct(){ 
     $db_connection = new dbConnection(); 
     $this->link = $db_connection->connect(); 
     return $this->link; 
    } 

    function registerUsers($password, $ip_address, $date, $time, $username, $email, $uname){ 
     $query = $this->link->prepare("INSERT INTO users (password,ip_address,date,time,username, email, uname) VALUES(?,?,?,?,?,?,?)"); 
     $values = array ($password, $ip_address, $date, $time, $username, $email, $uname); 
     $query->execute($values); 
     $count = $query->rowCount(); 
     return $count; 
    } 

    function LoginUsers($username, $password){ 
     $query = $this->link->query("SELECT * FROM users WHERE username='$username' AND password='$password'"); 
     $rowCount = $query->rowCount(); 
     return $rowCount; 
    } 

    function GetUserInfo($username){ 
     $query = $this->link->query("SELECT * FROM users WHERE username = '$username'"); 
     $rowCount = $query->rowCount(); 
     if($rowCount ==1) 
     { 
      $result = $query->fetchAll(); 
      return $result; 
     } 
     else 
     { 
      return $rowCount; 
     } 
    } 
} 
?> 

Answer 1

您probaly呼吁​​一个字符串，而不是对象。你能否验证你调用query（）的变量是否包含正确的对象，而不是错误地重写它？

Answer 2

@Bolivir是正确的：你得到的错误是因为$this-link是一个字符串，而不是一个对象。

难道$this->link = $db_connection->connect();也可以返回一个字符串而不是连接（例如，当您输入错误凭证或数据库关闭时）？

或者不应该$this->link请参考$db_connection？只是在这里尝试一些东西，因为我不知道你使用的是什么数据包封装。

dbConnection::connect() -method是什么样的？