此集合实例上不存在属性 [名称]

Question

我在数据库中有 3 个表（用户、区域、区域用户），

用户表：id 名称 用户名 密码

区域表：id 名称

area_user 表：id user_id area_id

我正在尝试创建一个（列表用户页面），它将显示用户分配区域的所有用户表列。

User.php 模型文件

  <?php

namespace App;

use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = ['name', 'email', 'password','role_id',];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = ['password', 'remember_token',];

    public function areas(){
        return $this->belongsToMany('App\Area','area_user');
    }

Area.php 模型文件：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Area extends Model{
    protected $fillable = ['name'];

    public function users(){
        return $this->belongsToMany('App\User','area_user','area_id','user_id');
    }
}

UserController@index 文件：

<?php

namespace App\Http\Controllers;

use App\Areas;
use App\Roles;
use App\User;
use Illuminate\Http\Request;

class UserController extends Controller{

    public function __construct(){
        // $this->middleware('auth');
    }

    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index(){
        $users = User::get();
        return view('users._list',
        ['users'=> $users]
    );
    }

最后是表视图文件：-

@foreach($users as $u)
            <tr role="row" class="odd">
                <td class="sorting_1">{{$u->name}}</td>
                <td></td>
                <td>{{$u->areas]}}</td>
                <td>{{route('show_user', ['id' => $u->id])}}</td>
            </tr></tbody>
@endforeach

如果我只使用区域属性（$u->areas）在用户表视图（指定区域）中输入，它将显示所有区域列：-

[
  {
    "id": 3,
    "name": "C",
    "location_id": 1,
    "created_at": null,
    "updated_at": null,
    "pivot": {
      "user_id": 4,
      "area_id": 3
    }
  },
  {
    "id": 4,
    "name": "D",
    "location_id": 2,
    "created_at": null,
    "updated_at": null,
    "pivot": {
      "user_id": 4,
      "area_id": 4
    }
  }
]

---

 @foreach($users as $u)
                <tr role="row" class="odd">
                    <td class="sorting_1">{{$u->name}}</td>
                    <td></td>
                    <td>{{$u->areas->name]}}</td>
                    <td>{{route('show_user', ['id' => $u->id])}}</td>
                </tr></tbody>
    @endforeach

请注意，如果我在上述视图 ($u->areas->name) 中指定区域关系中的列名，则会显示错误：-

此集合实例上不存在属性 [名称]。（查看：C:\xampp\htdocs

如何在视图文件中仅显示 (areas.name) 列

Answer 1

因为它areas是一个集合，所以你应该像这样循环它：

@foreach($users as $u)
    <tr role="row" class="odd">
        <td class="sorting_1">{{$u->name}}</td>
        <td></td>
        <td>
        @foreach($u->areas as $area)
            {{$area->name}}, 
        @endforeach
        </td>
        <td>{{route('show_user', ['id' => $u->id])}}</td>
    </tr></tbody>
@endforeach

如果你想用逗号将它们分开，例如你可以这样做而无需循环：

    @foreach($users as $u)
    <tr role="row" class="odd">
        <td class="sorting_1">{{$u->name}}</td>
        <td></td>
        <td>
            {{ $u->areas->pluck('name')->implode(', ') }}
        </td>
        <td>{{route('show_user', ['id' => $u->id])}}</td>
    </tr></tbody>
@endforeach