Symfony 2.8注入RequestStack错误(Symfony 2.8 injecting RequestStack error)

 我有注入RequestStack的问题。 
 
 在这种情况下，如果我只使用请求，一切都很好： 
 
<?php

namespace Cms\AdminBundle\Controller;

use Symfony\Component\HttpFoundation\Request;

...
class DefaultController extends BaseController {
    public function mainAction(Request $request) {
...
 
 但是，如果我尝试使用RequestStack，我会收到错误“Controller”Cms \ AdminBundle \ Controller \ DefaultController :: mainAction（）“要求您为”$ requestStack“参数提供一个值（因为没有默认值或因为那里在这之后是一个非可选参数。）“ 
 
 这是代码： 
 
namespace Cms\AdminBundle\Controller;

use Symfony\Component\HttpFoundation\RequestStack;

...
class DefaultController extends BaseController {
    public function mainAction(RequestStack $requestStack) {
...
 
 谢谢！ 

I have problem with injecting RequestStack.
 
In this case, if I use just Request, everything is fine:
 
<?php

namespace Cms\AdminBundle\Controller;

use Symfony\Component\HttpFoundation\Request;

...
class DefaultController extends BaseController {
    public function mainAction(Request $request) {
...
 
But if I try to use RequestStack, I get error "Controller "Cms\AdminBundle\Controller\DefaultController::mainAction()" requires that you provide a value for the "$requestStack" argument (because there is no default value or because there is a non optional argument after this one)."
 
Here is the code: 
 
namespace Cms\AdminBundle\Controller;

use Symfony\Component\HttpFoundation\RequestStack;

...
class DefaultController extends BaseController {
    public function mainAction(RequestStack $requestStack) {
...
 
Thank you!

原文：