Laravel 路由模型绑定不起作用

我try 对简单的CRUD使用路由模型绑定，但更新和删除功能不起作用.我用的是LARAVEL 5.5

Route::resource('admin/file','AdminController');

My View For Edit and Delete Buttons

<a href="{{ route('file.edit', ['id'=>$file->id]) }}">

<form action="{{ route('file.destroy', ['id'=>$file->id]) }}" method="post">
   {{method_field('DELETE')}}
   {{csrf_field()}}
   <button type="submit" class="delete">delete</button>
</form>

My Resource Controller :

namespace App\Http\Controllers;

use App\Files;
use Illuminate\Http\Request;

Store Work Fine

  public function store(Request $request)
{
    $this->validate($request,[
        'title'=>'required',
        'body'=>'required',
        'price'=>'required',
        'linkFile'=>'required',
    ]);

     Files::create($request->all());
    return redirect(route('file.index'));
}

但是编辑和删除不起作用

public function edit(Files $files)
{
   return view('admin.edit',compact('files'))->with('title','Edit File');
}

public function destroy(Files $files)
{
    $files->delete();
    return redirect(route('file.index'));
}

我的模特:

protected $table='files';

protected $fillable=[
    'title','body','price','linkFile'
];

当我删除按钮时，没有任何react ，编辑方式相同

If I Add dd($files) at First Column for Edit and Delete Function Then Response Will be [] and There's No Error for handle

这里是我的路由列表

Anyone Can help Please?