Laravel - 控制器中的公共变量

Question

我希望有一个公共变量$users = User::all();，所以我可以在控制器内的不同方法中使用它，它不会这样工作：

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use App\User;

class AdminController extends Controller
{

    public $users = User::all();

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


    public function index()
    {
        return view('admin.index');
    }

    public function showUsers()
    {

        return view('admin.users', compact('users'));
    }
}

我收到此错误：常量表达式包含无效操作

我做错了什么？

Answer 1

尝试将分配添加到__construct()功能中：

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use App\User;

class AdminController extends Controller
{

    public $users;

    public function __construct() {
        $this->users = User::all();
        $this->middleware('auth');
    }


    public function index()
    {
        return view('admin.index');
    }

    public function showUsers()
    {
        $users = $this->users;
        return view('admin.users', compact('users'));
    }
}

Answer 2

您需要在构造函数中初始化$users：

<?php

public $users;

public function __construct() {
    $this->middleware('auth');
    $this->users = User::all();
}