Laravel 5.3 How to use multiple controllers in one view - laravel

Question

I'm working with a view that at first displays all products, and on the sidebar, users can see a list of categories. My aim is when users press on any categories, it will display products of that category only. However, since there are 2 controllers is interacting with this view and send the same data, one is not running(CategoriesController). It does not show any error, just when I click on the link of each of the categories, it does not reload the page.
Here is my ProductsController:
class ProductsController extends Controller
{
// display all products and categories
public function index() {
$products = Product::all();
$categories = Category::all();
return view('frontend.product', compact('products','categories'));
}
And my CategoriesController:
class CategoriesController extends Controller
{
public function showProducts($category_id) {
$products = Category::find($category_id)->products;
return view('frontend.product', compact('products'));
}
Here is my view:
// Products part
#foreach($products as $product)
{{ $product->name }}
#endforeach
//Categories part
#foreach($categories as $category)
{{ $category->name }}
#endforeach
And route:
Route::get('/products', [ 'as' => 'products', 'uses' => 'frontend\ProductsController#index']);
Route::get('/categories/{category_id}', ['as' => 'categories', 'uses' => 'backend\CategoriesController#showProducts']);

Answer 1

Just include all of the categories in your showProducts function, and omit the current category:
public function showProducts($category_id)
{
$categories = Category::whereNotIn('id', $category_id)->get();
$products = Category::find($category_id)->products;
return view('frontend.product', compact('products', 'categories'));
}
Now there will be no discrepancies between the variables that are being used.

Answer 2

If I have not misunderstood, I thought you can use #inject in blade. For example:
namespace App\Presenters;
use App\User;
class UserPresenter
{
/**
* 是否顯示email
* #param User $user
* #return string
*/
public function showEmail(User $user)
{
if ($user->show_email == 'Y')
return '<h2>' . $user->email . '</h2>';
else
return '';
}
}
and
<div>
#inject('userPresenter', 'MyBlog\Presenters\UserPresenter')
#foreach($users as $user)
<div>
{!! $userPresenter->showEmail($user) !!}
</div>
</div>