Creating a var from data created by another class

I am having problems creating a variable with data from another class. Here is what I am doing...

 <?PHP
  class Customers extends Con开发者_C百科troller {

      private $foo = $this->session->userdata('foo');
  }

You probably want something more like this:

class Customers extends Controller 
{
  private $foo;
  public function __construct()
  {
    parent::__construct();
    $this->foo = $this->session->userdata('foo');
  }
}

It's hard to know for sure without knowing more about your project.

You can set it with constructor because you are inhering from parent class:

class Customers extends Controller {
  private $foo = null;

  function __construct(){
     parent::__construct();
     $this->foo = $this->session->userdata('foo');
  }
}

This is not possible: $this doesn't exist at the moment when you define the class, and you can't call functions at all at this point at all.

You will need to assign $foo in the constructor, after $this->session has been initialized. (@konforce beat me to the example.)