我有问题与验证html选择。我把规则和所有其他表单控件工作正常，但只有选择不显示验证消息。

• • 型号**

class Post extends Model
{
    
    protected $table = 'post';

   
static $rules = [
'title' => 'required',
    'slug' => 'required',
'user_id' => 'required|not_in:0',
    'meta_title' => 'required',
    'meta_description' => 'required',
'post_category_id' => 'required'
];
}

"刀锋"

<div class="form-group">
    {{ Form::label('post_category_id', 'Category') }}
    <select name="post_category_id" class="form-control">
        <option value="0">Select Category</option>
        @foreach($categories as $category)
        <option value="{{ $category->id }}" {{ $category->id == $post->post_category_id ? 'selected' : ''}}>{{ $category->name }}</option>
        @endforeach
    </select> {!! $errors->first('post_category_id', '<div class="invalid-feedback">:message</div>') !!}
</div>

• • 主计长**

public function store(Request $request)
    {
        request()->validate(Post::$rules);

        $post = Post::create($request->all());

        Alert::alert('Success', 'Post created successfully.', 'Type');

        return redirect()->route('admin.post.index');
    }

我做错了什么？