php - Laravel isEmpty 不起作用

Question

当我尝试使用 isEmpty 函数检查模型是否为空时，Laravel 5.6 出现错误。

型号:

namespace App\Models\Projectmanagement;

use Illuminate\Database\Eloquent\Model;

class Projects extends Model
{
    protected $table = 'projects';
    public $timestamps = false;
}

Controller :

public function create()
{
    $project = new Projects;
    return view('pages.projectmanagement.projects.edit', [
        'project' => $project,
        'companies' => Company::all(),
    ]);
}

查看:

<form method="post">
  {{ csrf_field() }}
  @if($project->isEmpty())
      @method('PUT')
   @endif
</form>

我的想法是我重用 edit.blade View 文件来创建和更新数据，所以我需要检查模型是否为空以在 View 文件中进行适当的更改。

但在这种情况下，Laravel 5.6 会抛出错误:

Method Illuminate\Database\Query\Builder::isEmpty does not exist. (View: /var/www/resources/views/pages/projects/edit.blade.php)

Answer 1

另一种方法是使用 Model exists 变量。例如:

//Case 1
$project = new Projects;
$project->exists; //Has false

//Case 2
$project = Projects::first();
$project->exists; //Has true

引用:https://laravel.com/api/5.6/Illuminate/Database/Eloquent/Model.html