Codeigniter模型致命错误：不在对象上下文中时使用$ this [英] Codeigniter Model Fatal error: Using $this when not in object context

问题描述

我对一些适用于开发但不适用于生产的代码有一点问题。这很奇怪，因为所有其他代码都起作用（或似乎起作用）。

I have a little issue with some code that works on development but not on production. It is weird, because all the other code works (or seems to).

整个错误如下：

致命错误：在
/[snip]/application/modules/manage_plugins/models/Manage_plugins.php
中不在对象上下文中时，使用$ this遇到PHP错误

Fatal error: Using $this when not in object context in /[snip]/application/modules/manage_plugins/models/Manage_plugins.php on line 6 A PHP Error was encountered

严重性：错误

消息：在对象上下文中不使用$ this

Message: Using $this when not in object context

文件名：models / Manage_plugins.php

Filename: models/Manage_plugins.php

行号：6

回溯：

从我发现的其他类似问题中，这是由于人们试图在其中使用 $ this静态上下文-我认为情况并非如此。

From the other similar issues I could find, it was due to people attempting to use "$this" in a static context - I don't believe that is the case for me.

这里是manage_plugins构造函数，第6行（错误行）是该构造函数的第一行：

Here is the manage_plugins constructor, with line 6 (error line) being the first in the constructor:

class Manage_plugins extends CI_Model {

    public function __construct() {
        $this->mediator->attach("manage_load", function($name, $data) { $this->on_manage_load(); });

        $this->load->model("automediator");
    }

}

正在由以下文件加载代码（从未明确调用过）：

It is being loaded by the following code (and never called explicitly):

$CI =& get_instance();

$CI->load->model("manage_plugins/manage_plugins");

有人知道为什么会这样吗？

Does anyone know why this is happening?

推荐答案

感谢rexmarc，我能够解决此问题，并通过 use -ing a使类似的结构在PHP 5.3上工作对象 $ this 在匿名函数中的副本。

Thanks to rexmarc, I was able to workaround the issue and make a similar structure work on PHP 5.3 by use-ing a copy of the object $this in the anonymous function.

我更改了以下内容：

class Manage_plugins extends CI_Model {
    public function __construct() {
        $this->mediator->attach("manage_load", function($name, $data) { $this->on_manage_load(); });

        $this->load->model("automediator");
    }

}

成：

class Manage_plugins extends CI_Model {
    public function __construct() {
        $me =& $this;
        $this->mediator->attach("manage_load", function($name, $data) use($me) { $me->on_manage_load(); });

        $this->load->model("automediator");
    }

}

对此的另一种解决方案是：

Another solution for this could have been:

class Manage_plugins extends CI_Model {
    public function __construct() {
        $this->mediator->attach("manage_load", [$this, 'on_manage_load']);

        $this->load->model("automediator");
    }

}

出现此问题是因为在PHP中5.4之前的版本中， $ this 在匿名函数中不可用。

The issue was occurring because in PHP versions prior to 5.4, $this was not available in anonymous functions.

5.4.0-匿名函数可以使用$ this并进行静态声明

5.4.0 - Anonymous functions may use $this, as well as be declared statically

来源： http：// php。 net / manual / en / functions.anonymous.php

由于开发版本（5.5）和生产版本（5.3）上的PHP版本不同，因此未引起注意。

The issue went unnoticed because of differing PHP versions on development (5.5) and production (5.3).

另请参见： https://stackoverflow.com/a/19432335/ 3649573

这篇关于Codeigniter模型致命错误：不在对象上下文中时使用$ this的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！