Calling class method from string stored as class member

问题

I am trying to call a method stored as $_auto, but it will not work.

<?php
    class Index {
        private $_auto;

        public function __construct() {
            $this->_auto = "index";
            $this->_auto();
        }

        public function index() {
            echo "index";
        }
    }

    $index = new Index();
?>

回答1:

You need to use call_user_func to do this:

call_user_func(array($this, $this->_auto));

Unfortunately PHP does not allow you to directly use property values as callables.

There is also a trick you could use to auto-invoke callables like this. I 'm not sure I would endorse it, but here it is. Add this implementation of __call to your class:

 public function __call($name, $args)
 {
     if (isset($this->$name) && is_callable($this->$name)) {
         return call_user_func_array($this->$name, $args);
     }
     else {
         throw new \Exception("No such callable $name!");
     }
 }

This will allow you to invoke callables, so you can call free functions:

 $this->_auto = 'phpinfo';
 $this->_auto();

And class methods:

 $this->_auto = array($this, 'index');
 $this->_auto();

And of course you can customize this behavior by tweaking what __call invokes.

回答2:

You code is trying to call a method called "_auto". To do what you are asking, you want to make the method name a php variable or something along the lines of what the other posters are saying.

class Foo {
    private function _auto() {
        echo "index";
    }

    public function callmethod($method) {
        $this->$method();
    }
}

$foo = new Foo();
$foo->callmethod('_auto');

回答3:

You don't have a method named _auto(), you only have a property named $_auto. If your intent is for a call to an undefined method to return a similarly named property if it exists, then you would need to write a __call() magic method to perform the logic of looking at a similarly named property and returning the value. So something like this would need to be added to your class:

public function __call($called_method, $arguments) {
    if(property_exists($this, $called_method)) {
        return $this->{$called_method};
    } else {
        throw new Exception('Illegal method call.');
    }
}

回答4:

I think you mistakenly defined "_auto" as a property?

Try using:

private function _auto(){}

Instead of

private $_auto

来源：https://stackoverflow.com/questions/14613210/calling-class-method-from-string-stored-as-class-member