类User的对象无法转换为字符串

Question

    public function login($username,$password) 
    {
    $thid->newUser = $this->conn->$this->query("SELECT COUNT(id) FROM user WHERE username = :username and password = :password",
                array(':username' => $username,
                        ':password' => $password
                    )); 
    }

我想使用正确的用户名和密码登录。

if($_SERVER['REQUEST_METHOD'] == "POST") {
        $username = $_POST['username'];
        $password = $_POST['password'];
        if(empty($username) || empty($password)) {

            $data = array('status' => 'Please enter your Username and Password');

        } else {
            $login = $user->login($username,$password); 
            $count = $login->fetchColumn();
            if($count == 1) {

                $user->redirectURL('home.php');
            } else {
                $data = array('status' => 'Wrong Username or Password');
            }

        }
    } else {
        $data = '';
    }

它说：可捕获的致命错误：类的对象在执行时无法转换为字符串。