php - Symfony2 Cannot instantiate interface in dependency injection -

php - Symfony2 Cannot instantiate interface in dependency injection -

i have problem when seek create service in symfony2.

this services.yml

services: menu: class: my\webbundle\classes\system\menu arguments: [@service_container]

this service menu:

namespace my\webbundle\classes\system; utilize symfony\component\dependencyinjection\containerinterface container; class menu{ private $container; public function __construct(container $container) { $this->container = $container; } public function getmenu($section) { homecoming "hello"; } }

when in controller do:

$menu = $this->get('menu');

i get:

fatalerrorexception: error: cannot instantiate interface my\webbundle\classes\system\menu in ...\cache\dev\appdevdebugprojectcontainer.php line 1522

of course of study cleaned cache.

change utilize statement to;

use symfony\component\dependencyinjection\container;

also redeclare arguments enclosing service name in quotes.

services: menu: class: my\webbundle\classes\system\menu arguments: ["@service_container"]

i question why injecting whole container though. why not inject parts need?

if defining controller service also, can access menu service injecting controller.

extra per comment request;

services: menu: class: my\webbundle\classes\system\menu arguments: ["@router"]

and class like;

<?php namespace my\webbundle\classes\system; utilize symfony\component\routing\routerinterface; class menu{ private $router; public function __construct(routerinterface $router) { $this->router = $router; } public function getmenu($section) { homecoming "hello"; } }

php symfony2 dependency-injection