此收集实例上不存在属性[项目]。 laravel 5.4

Question

帮助或协助，因为它不会对类别进行排序，我不明白为解决这个问题。 我最近学习laravel。

控制器：class ArticlesController

public function showAll ($category_id) 
{ 
    $categories = Category::where('name', $category_id)->get(); 
    return view('categories')->with(compact('categories', 'articles')); 
} 

这一观点从中我想进入的类别。 site.blade.php

@foreach($categories as $category) 
     <li><a class="nav-link text-white" href={{route('articlesShow', ['id'=>$category->id]) }}">{{ $category->name }}</a></li> 
@endforeach 

路线：

Route::get('/categories/{category_id}', 'ArticlesController@showAll')->name('articlesShow'); 

型号：类别

public function articles() 
{ 
    return $this->hasMany(Article::class, 'category_id'); 
} 

表示在没有得到得到：categories.blade.php

@foreach($categories->articles as $article) 
      <div class="col-6 col-lg-4"> <!--Post --> 
      <img src="{{ asset('upload/image/1.jpg') }}" width="255" alt="..." class="rounded img_size"> 
      <h4> {{ $article->title }}</h4> 
      <h6>Category: <a href="/"> {{ $article->category->name }}</a></h6> 
      <h6>Author: {{ $article->author }}</h6> 
      <p>{{ $article->text }} </p> 
      <p><a class="btn btn-secondary" href="{{ route('articleShow', ['id' =>$article->id]) }}"> More &raquo;</a></p> 
      </div><!--EndPost--> 
@endforeach 

Answer 1

$类是包含类别的n数组，并且文章属性属于一个类别，因此在访问文章之前必须循环分类。

试试这个：

@foreach($categories as $category) 
@foreach($category->articles as $article) 
     <div class="col-6 col-lg-4"> <!--Post --> 
     <img src="{{ asset('upload/image/1.jpg') }}" width="255" alt="..." class="rounded img_size"> 
     <h4> {{ $article->title }}</h4> 
     <h6>Category: <a href="/"> {{ $article->category->name }}</a></h6> 
     <h6>Author: {{ $article->author }}</h6> 
     <p>{{ $article->text }} </p> 
     <p><a class="btn btn-secondary" href="{{ route('articleShow', ['id' =>$article->id]) }}"> More &raquo;</a></p> 
     </div><!--EndPost--> 
@endforeach 
@endforeach 

Answer 2

首先：使用eager loading。

假设，你ArticlesController@showAll方法应该显示给定类别ID的所有文章，您的查询应该是这样的

public function showAll ($category_id) 
{ 
    $categoryArticles = Category::with('articles')->where('id', $category_id)->get(); 
    return view('categories')->with('categoryArticles', $categoryArticles); 
} 

然后以显示给定类别的所有文章（假设一篇文章只有一个类别） ，这可能是一种方式：

@foreach($categoryArticles->articles as $article) 
      <div class="col-6 col-lg-4"> <!--Post --> 
      <img src="{{ asset('upload/image/1.jpg') }}" width="255" alt="..." class="rounded img_size"> 
      <h4> {{ $article->title }}</h4> 
      <h6>Category: <a href="/"> {{ $categoryArticles->name }}</a></h6> 
      <h6>Author: {{ $article->author }}</h6> 
      <p>{{ $article->text }} </p> 
      <p><a class="btn btn-secondary" href="{{ route('articleShow', ['id' =>$article->id]) }}"> More &raquo;</a></p> 
      </div><!--EndPost--> 
@endforeach