component dependecies: Added EN translation (#492)

Author: zraly

en/components.texy

@@ -203,6 +203,86 @@ This parameter will be automatically passed in every link as a `GET` parameter u
 .[caution]
 Never trust persistent parameters blindly because they can be faked easily (by overwriting the URL). Verify, for example, if the page number is within the correct interval.
 
+Components with dependencies
+===========================
+
+When our component needs some things to work, like `PollControl` needs `PollManager` to manage voting and save polls, it can be done by [injecting these dependencies | dependency-injection]  into the constructor:
+
+/--php
+class PollControl extends Control
+{
+    /**
+     * @var App\Model\PollManager
+     */
+    private pollManager;
+
+    /**
+     * @var int Id of a poll, for which the component is created
+     */
+    private $pollId;
+
+    /**
+     * @param $pollId
+     * @param App\Model\PollManager $pollManager model providing the voting
+     */
+    public function __construct($pollId, PollManager $pollManager)
+    {
+        $this->pollManager = $pollManager;
+        $this->pollId = $pollId
+    }
+
+    /**
+     * @param $voteId Option Id we voted for
+     */
+    public function handleVote($voteId)
+    {
+        $this->pollManager->vote($pollId, $voteId);
+        //...
+    }
+}
+\--
+
+OK, but how the `PollManager` is put into the `PollControl`'s constructor? That's job for [DI | dependency-injection] container. It put it there automatically through an interface we provide it:
+
+/--php
+interface IPollControlFactory
+{
+    /**
+     * @param $pollId
+     * @return PollControl
+     */
+    public function create($pollId);
+}
+\--
+
+And this interface has to be registered in our container in [neon | configuring#toc-custom-services]:
+
+
+/--neon
+services:
+    - IPollControlFactory
+\--
+
+Finally, we will use this factory in our presenter:
+
+/--php
+class PollPresenter extends \Nette\UI\Application\Presenter
+{
+    /**
+     * @var IPollControlFactory
+     * @inject
+     */
+    public $pollControlFactory;
+
+    protected function createComponentPollControl()
+    {
+        $pollId = 1; // we can pass our parameter
+        return $this->pollControlFactory->create($pollId);
+    }
+}
+\--
+
+That's all. Nette internally implements this interface and injects it to our presenter, where we can use it. It also magically passes our parameter `$pollId` and instance of class `App\Model\PollManager` into our component.
 
 Advanced use of components
 ==========================