laravel 请求文件返回 null

Question

this question have been asked many times before, I've tried all the solutions but nothing work with me

   "laravel/framework": "^6.0",

//-----

   <form  action="post_customer_data" id="editform" method="POST" class="form-horizontal" enctype="multipart/form-data">
    <input id="logo" type="file" name="logo" class="form-control  form-control-lg">

  dd($request->file('logo')); //Return Null!!!

in controller i use all the required packages

use Storage;
use File;
use Intervention\Image\Facades\Image;
use Illuminate\Http\Request;

Answer 1

What are the result if you print all the request data? Something like that:

dd($request->all());