此收集實例上不存在屬性[項目]。 laravel 5.4

Question

幫助或協助，因爲它不會對類別進行排序，我不明白爲解決這個問題。 我最近學習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')); 
} 

這一觀點從中我想進入的類別。 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 

路線：

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

型號：類別

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

表示在沒有得到得到：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

$類是包含類別的n數組，並且文章屬性屬於一個類別，因此在訪問文章之前必須循環分類。

試試這個：

@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。

假設，你ArticlesController@showAll方法應該顯示給定類別ID的所有文章，您的查詢應該是這樣的

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

然後以顯示給定類別的所有文章（假設一篇文章只有一個類別） ，這可能是一種方式：

@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