构造中的PHP未定义变量

Question

这是我的代码：

<?php
require dirname(__DIR__).'/config/Redirect.php';

class Parsing {

    private $controller = null;
    private $model = null;
    private $parameters = array();

    private $redirect;

    public function __construct() {
        $this->redirect = new Redirect($controller, $model, $parameters); //error is on this line
    }

}
?>

我得到的错误是这个（我删除了行号，但我评论了错误在上面代码中的位置）：

Notice: Undefined variable: controller in /var/www/html/application/config/Parsing.php on line #

Notice: Undefined variable: model in /var/www/html/application/config/Parsing.php on line #

Notice: Undefined variable: params in /var/www/html/application/config/Parsing.php on line #

似乎控制器已经定义在它之上，例如private $controller = null;和所有其他控制器。可能是什么问题？

Answer 1

将行更改为：

$this->redirect = new Redirect($this->controller, $this->model, $this->parameters);

Answer 2

使用$this关键字调用类级别变量

public function __construct() {
        $this->redirect = new Redirect($this->controller, $this->model, $this->parameters); 
    }

Answer 3

您需要$this关键字，例如$this->controller，$this->model，$this->parameters

public function __construct() {
        $this->redirect = new Redirect($this->controller, $this->model, $this->parameter); //error is on this line
}