访问另一个PHP文件中的类变量

Question

I want to use variables in another php file as the class. But I get always the error: Notice: Undefined variable:...

First: I create a user object: File: index.php

<?php

// include the configs / constants for the db connection
require_once("config/config.php");

// load the user class
require_once("classes/User.php");

$user = new User();

include("views/order.php");

File: User.php

class User
{
   public $color = "green";
}

File livesearch.php

require_once("../classes/User.php");

echo $User->color;

I create an object from the class user in a index.php file, I use there also a require once to the User.php file and it works. Why I cant access the variable of the class?

Answer 1

Variable names in PHP are case sensitive:

echo $User->color;

should be

echo $user->color;

Also the livesearch.php doesn't have access to the variables in index.php unless:

• It is includes in index.php . In which case it has access to all the variables assigned in index.php before it was included.
• livesearch.php includes index.php . In which case it has access to all the variables assigned in index.php after the point where index.php was included.

eg. Your files, but slightly modified:

File: index.php

// load the user class
require_once("User.php");

$user = new User();

include("livesearch.php");

File: User.php

class User
{
   public $color = "green";
}

File: livesearch.php

echo $User->color;

Is the same as writing:

// From User.php
class User
{
   public $color = "green";
}

// From index.php
$user = new User();

// From livesearch.php
echo $User->color;

Answer 2

PHP for File livesearch.php :

 require_once("../classes/User.php");

 $user = new User;
 echo $user->color;

Answer 3

you should to use singleton of design patterns for speed. I do not recommend such a usage in this case. ( this->color instead user::color ).

research design pattern, polymorphism.

answer

• userclass.php class User { public $color = "green"; }

$User = new User;

• livesearch.php require_once("../classes/User.php");

echo $User->color;