PHP / CodeIgniter - 在__construct（）中设置变量，但不能从其他函数访问 [英] PHP/CodeIgniter - Setting variables in __construct(), but they're not accessible from other functions

问题描述

我很高兴一个变量范围问题。也许我只需要更多的咖啡...

这是我的（简化）代码 - 这是在CodeIgniter 2：

  class Agent extends CI_Controller {
 
 public function __construct（）
 {
 parent :: __ construct 
 
 $ this-> load-> model（'agent_model'）; 
 
 //获取将在代理函数中常用的初始数据
 $ user = $ this-> my_auth_library-> get_user（）; 
 $ agent = $ this-> agent_model-> get_agent（$ user-> id）; 
} 
 
 public function index（）
 {
 $ this-> template-> set（'info'，$ this-> agent_model-> ; get_info（$ agent-> id））; 
 
 $ this-> template-> build（'agent / welcome'）;不幸的是，当我运行索引函数时，我被告知：  
 
  
 
 
 遇到PHP错误
 
严重性：注意
消息：未定义变量：代理
文件名：controllers / agent.php 
行号：51 
  

51行第一行的索引函数。出了什么问题？这是范围问题还是其他问题？

谢谢！

解决方案

您尚未在索引操作中设置 $ agent ，如果您希望在构造函数中设置的变量可访问，则必须将它们设置为类属性ie： $ this-> Agent = ...; ，并以相同的方式使用 $ this-> Agent-> id 。 （我将它们大写，以表明它们是对象而不仅仅是变量）例如：

  $ this-& $ this-> my_auth_library-> get_user（）; 
 $ this-> Agent = $ this-> agent_model-> get_agent（$ user-> id）; 
  

构造函数的行为与任何其他类方法相同，它唯一的特殊属性是它会自动运行该类被实例化，正常的变量范围仍然适用。

I'm happy a bit of a variable scoping problem. Maybe I just need more coffee...

Here's my (simplified) code - this is in CodeIgniter 2:

class Agent extends CI_Controller {     

public function __construct()
{
    parent::__construct();

    $this->load->model('agent_model');

    // Get preliminary data that will be often-used in Agent functions
    $user   = $this->my_auth_library->get_user();
    $agent  = $this->agent_model->get_agent($user->id);
}

public function index()
{       
    $this->template->set('info', $this->agent_model->get_info($agent->id));

    $this->template->build('agent/welcome');
}

Unfortunately, when I run the index function, I'm told:

A PHP Error was encountered

Severity: Notice
Message: Undefined variable: agent
Filename: controllers/agent.php
Line Number: 51

Line 51 is the first line of the index function. What's going wrong? Is this a scope issue or something else?

Thanks!

解决方案

You haven't set $agent in your index action, if you want variables set in the constructor accessible then you have to set them as a class property ie: $this->Agent = ...;, and access them in the same way with $this->Agent->id. (I would capitalise them to show that they are objects and not just variables) For example:

$this->User   = $this->my_auth_library->get_user();
$this->Agent  = $this->agent_model->get_agent($user->id);

The constructor behaves the same as any other class methods, its only special property is that it's automatically ran when the class is instantiated, normal variable scope still applies.

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