如何在PHP中通过变量调用静态函数？

Question

When I use the code below it throws an error even though the function looks well formed. (FYI I also tried valid and static prefixes.)

---

Function call:

foreach ($this->errorList as $field => $error_msg) {
            // check for valid input and store cleaned vars
            $this->goodInput[$field] = Valid::__($field);
}

---

Result:

PHP Fatal error: Call to undefined function Valid::email()

---

Code:

class Valid
{
    public static function __($name)
    {
        // this is what I tried:
        // $checkFunction = 'self::' . $name;
        // return $checkFunction();

        // this works:
        // Thank you to fusion3k and Darren
        return self::$name();
    }

    private static function email()
    {
        //sanitize and validate email field
    }

    // other methods for other fields
    // ...

    // default method to sanitize input for display in email
    public static function __callStatic($name, $arguments)
    {
        if (array_key_exists($name, $_POST)) {
            $clean_var = trim($_POST[$name]);
            $clean_var = stripslashes($clean_var);    
            $clean_var = htmlspecialchars($clean_var);
            return $clean_var;
        } else {
            return '';
        }
    }
}

Answer 1

I assume you instantiate your class somewhere properly first right? Well it's best to check that a said method exists, and harness self:: . Also, as @fusion3k said , better to return self::$name() . Here's an example of what you should be doing:

public static function __($name) {
    if(method_exists(new self, $name)) {
        return self::$name();
    }
}

In all honesty, this isn't the best way for you to be doing it. You should be looking into call_func_user_array() to manage this kind of implementation properly. Allowing the parsing of arguments to called methods.

Answer 2

There is not any object created when you call an static function then Valid functions are not accessible. Try like this

public static function __($name) { 
$valid = new Valid ();
return $valid::$name(); 
}