How to use variable name to call a class?

Question

I want to use a variable (string value) to call a Class. Can I do it ? I search for PHP ReflectionClass but I do not know how to use a method from Reflection Result. Like this:

    foreach($menuTypes as $key => $type){
        if($key != 'Link'){
            $class = new \ReflectionClass('\App\Models\\' . $key);

            //Now $class is a ReflectionClass Object
            //Example: $key now is "Product"
            //I'm fail here and cannot call the method get() of 
            //the class Product

            $data[strtolower($key) . '._items'] = $class->get();
        }
    }

What do you mean saying to call a class? Do you want to create a class instance? — Ihor Burlachenko, Jan 28 '16 at 10:22
It looks like you don't need reflection. If you want to instantiate an object, you can do `$object = new $key();` — jeroen, Jan 28 '16 at 10:25
@jeroen & Ihor Burlachenko: this is exactly what I want. So simple, Thank you ! — Kieu Duy, Jan 28 '16 at 10:29
Possible duplicate of [In PHP 5 can I instantiate a class dynamically?](http://stackoverflow.com/questions/3112727/in-php-5-can-i-instantiate-a-class-dynamically) — SOFe, Jan 28 '16 at 10:30

score 3 · Accepted Answer · answered Jan 28 '16 at 10:24

3

Without ReflectionClass:

$instance = new $className();

With ReflectionClass: use the ReflectionClass::newInstance() method:

$instance = (new \ReflectionClass($className))->newInstance();

answered Jan 28 '16 at 10:24

SOFe

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score 2 · Answer 2 · answered Jan 28 '16 at 10:26

2

I found one like this

$str = "ClassName";
$class = $str;
$object = new $class();

answered Jan 28 '16 at 10:26

magic-sudo

1,206
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score 2 · Answer 3 · answered Jan 28 '16 at 10:26

2

You can use directly like below

$class = new $key();

$data[strtolower($key) . '._items'] = $class->get();

answered Jan 28 '16 at 10:26

Edwin Alex

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schellingerht · Answer 4 · 2016-01-28T10:57:28.967

0

The risk is that the class doesn't exist. So it's better to check before instantiating.

With php's class_exists method

Php has a built-in method to check if the class exists.

$className = 'Foo';
if (!class_exists($className)) {
    throw new Exception('Class does not exist');
}

$foo = new $className;

With try/catch with rethrow

A nice approach is trying and catching if it goes wrong.

$className = 'Foo';

try {
    $foo = new $className;
}
catch (Exception $e) {
    throw new MyClassNotFoundException($e);
}

$foo->bar();

edited Jan 28 '16 at 10:57

answered Jan 28 '16 at 10:43

schellingerht

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Yes, you can with try/catch. Try to instantiate > class doesn't exist > exception > class not found – schellingerht Jan 28 '16 at 10:52

How to use variable name to call a class?

4 Answers4

With php's class_exists method

With try/catch with rethrow