Getting static property from a class with dynamic class name in PHP

php oop dynamic static properties
treznik picture treznik · Aug 14, 2009 · Viewed 36.9k times · Source

I have this:

  • one string variable which holds the class name ($classname)
  • one string variable with holds the property name ($propertyname)

I want to get that property from that class, the problem is, the property is static and I don't know how to do that.

If the property weren't static, it would have been:

$classname->$propertyname;

if the property were a method, I could have used call_user_function

call_user_func(array($classname, $propertyname));

But in my case, am I just lost. I am however hoping that it is possible. With the thousands of functions that PHP has, he'd better have something for this as well. Maybe I'm missing something?

Thanks!

Edit:

  • for those with eval() solutions: thanks, but it is out of the question
  • for those with get _class _vars() solutions: thanks, but it seems it returns "the default properties of the given class" (php.net), and yes, I would like that value to be changable (even though it does help me in some of the cases)

Answer

Andrew Moore picture Andrew Moore · Aug 14, 2009

If you are using PHP 5.3.0 or greater, you can use the following:

$classname::$$propertyname;

Unfortunately, if you are using a version lower than 5.3.0, you are stuck using eval() (get_class_vars() will not work if the value is dynamic).

$value = eval($classname.'::$'.$propertyname.';');

Related questions

When to use self over $this?

In PHP 5, what is the difference between using self and $this? When is each appropriate?

Read More
What is the difference between public, private, and protected?

When and why should I use public, private, and protected functions and variables inside a class? What is the difference between them? Examples: // Public public $variable; public function doSomething() { // ... } // Private private $variable; private function doSomething() { // ... } // Protected protected $variable; protected function …

Read More
How do I get a PHP class constructor to call its parent's parent's constructor?

I need to have a class constructor in PHP call its parent's parent's (grandparent?) constructor without calling the parent constructor. // main class that everything inherits class Grandpa { public function __construct() { } } class Papa extends Grandpa { public function __construct() { // call Grandpa's constructor …

Read More