CodeIgniter中出现Undefined variable: menu错误，请求排查解决

Hey there! I see exactly what's causing that error—you're using an extra dollar sign when accessing your class property. Let's break this down and fix it.

The Root Cause #

Your code uses $this->$menu when trying to access the private class property $menu. This syntax is for variable variables in PHP, which means PHP is looking for a local variable named $menu (which you haven't defined) to use as the property name. What you actually want is to directly reference the class property with $this->menu.

Corrected Code #

Here's the fixed version of your Dashboard controller:

<?php 
class Dashboard extends CI_Controller { 
    private $menu; 

    public function __construct() { 
        parent::__construct(); 
        $this->load->model('menu_model'); 
        // Removed the extra $ from $this->$menu
        $this->menu = $this->menu_model->generateTree($items = array()); 
    } 

    public function index() { 
        // Also removed the extra $ here
        $data['menu'] = $this->menu; 
        $this->load->view('dashboard/dashboard', $data); 
    } 
} 

Key Fixes #

• In the constructor: Changed $this->$menu to $this->menu when assigning the menu data from your model
• In the index() method: Changed $data['menu'] = $this->$menu; to $data['menu'] = $this->menu; to correctly pass the class property to your view

This should eliminate the "Undefined variable: menu" error while keeping your menu functionality working as expected.

内容的提问来源于stack exchange，提问作者Thisaru