Want to use both Request::ajax() and Request to get form data

In Laravel 5.5 i want to use Request::ajax() function and for that i have to replace use Illuminate\Http\Request with use Request
After replacing namespace ajax function is working fine, but i also want to get form parameters, when i try to use public function ajax_form(Request $request) and $request->parameter it gives me this error:

Undefined property: Illuminate\Support\Facades\Request::$parameter

How can i get form parameters at same time using that ajax function?

via Chebli Mohamed