致命错误:在第 15 行的非对象上调用成员函数 prepare()

Question

任何人都可以帮我找出这个代码博客中的错误吗？ 代码在这里：..........

<?php
include_once('classdatabase.php');
class ManageUsers{
    public $link;
    function __construct(){
        $db_connection= new dbConnection();
        $this->link=$db_connection->connect();
        return $this->link;
    }
    function registerUsers($username,$password){
       // include_once('classdatabase.php');
        $query=$this->link->prepare("insert into users (username, password) VALUES (?,?)");// the error is just noticed this line !
        $values=array($username,$password);
        $query->execute($values);
        $count=$query->rowCount();
        return $count;
    }
}
$users= new ManageUsers();
echo $users->registerUsers('emi','emi');

?>

接下来这是另一个PHP类文件（classdatabase.php），其中我被声明为主数据库连接，代码如下：

<?php
class dbConnection{
   protected $db_conn;
    public $db_name='todo';
    public $db_user='root';
    public $db_pass='';
    public $db_host='localhost';
    function connect(){
    try{   $this->db_conn= new PDO("mysql:host= $this->db_host;dbname=$this->db_name",$this->db_user,$this->db_pass);
        return $this->db_conn;
    } catch(PDOException $e){
        return $e->getMessage();
    }
    }
}
?>

有一个错误，错误-

致命错误：在 C：\wamp\www\Todo\Classes\class 中的非对象上调用成员函数 prepare（）。管理用户.php在第 15 行

Answer 1

您需要访问您的$this->db_conn。试试这些模组。我已经在我自己的数据库上测试了它，它可以正常工作。如果您仍然遇到问题，那么您可能需要检查您是否使用了正确的连接凭据，因为这不起作用的唯一方法是连接失败并返回错误而不是类 （ $this ）：

class dbConnection
    {
        // Create public connection
        public $db_conn;
        public $db_name =   'todo';
        public $db_use  =   'root';
        public $db_pass =   '';
        public $db_hos  =   'localhost';
        public  function connect()
            {
                try {
                        // Try concatenating your db credentials
                        $this->db_conn = new PDO('mysql:host='.$this->db_host.';dbname='.$this->db_conn,$this->db_user,$this->db_pass);
                        // return $this only
                        return $this;
                    }
                catch(PDOException $e) {
                        // Try exiting and printing the error.
                        print_r($e->errorInfo());
                        exit;
                    }
            }
    }
    class ManageUsers
        {
            public  $link;
            public  function __construct(){
                $db_connection  =   new dbConnection();
                // Assign method chained connection
                $this->link     =   $db_connection->connect()->db_conn;
            }
            function registerUsers($username,$password){
               // include_once('classdatabase.php');
                $query  =   $this->link->prepare("insert into users (username, password) VALUES (?,?)");// the error is just noticed this line !
                $values =   array($username,$password);
                $query->execute($values);
                $count  =   $query->rowCount();
                return $count;
            }
        }
$users  =   new ManageUsers();
echo $users->registerUsers('emi','emi');