Question

我是Laravel的新手，这是我的第一个问题。我有3张桌子：

类别：ID，名称（目前有2个项目）

变体：ID，名称

category_variant：id，category_id，variant_id； <- 每个变体都有1或2个类别

在VariantController中，我有以下代码：

public function edit($id)
{
    $variant = Variant::where('id', $id)->with('categories')->first();
    $categories = Category::all();

    return view('admin.variant.edit', compact('variant', 'categories'));
}

在edit.blade.php中，我有以下html：

@foreach ($categories as $key=>$category)
   <div class="form-group form-float">
   @if (isset($variant->categories[$key]->pivot->category_id)) <-- I think here is the problem
      <input type="checkbox" id="wb" class="filled-in" name="wb" value="{{$category->id}}" {{ $category->id == $variant->categories[$key]->pivot->category_id  ? 'checked' : ''}} >
      <label for="wb">{{ $category->name}}</label>
   @else
      <input type="checkbox" id="wb" class="filled-in" name="wb" value="{{$category->id}}">
      <label for="wb">{{ $category->name}}</label>
   @endif
   </div>
@endforeach

我想知道在复选框中选中了哪个类别。如果该变体具有全部2个类别，那么一切都可以，但是如果用户只选择了一个类别，则会出现错误

Undefined offset: 1 (View: /shui/resources/views/admin/variant/edit.blade.php)

如何解决此问题？提前致谢迪米

Answer 1

您可以使用collection的力量：

@if($variant->categories->contains($category))
    {{--  You does not need to test a second time to know if you need to "check" --}}
    <input type="checkbox" id="wb" class="filled-in" name="wb" value="{{$category->id}}" checked >
    <label for="wb">{{ $category->name}}</label>
@else
    {{-- Do stuff --}}
@endif

或更简单。删除第一个@if

<input type="checkbox" id="wb" class="filled-in" name="wb" value="{{$category->id}}" $variant->categories->contains($category)? 'checked' : '' >
<label for="wb">{{ $category->name}}</label>

还可以在Controller中简化

$variant = Variant::where('id', $id)->with('categories')->first();

与

$variant = Variant::with('categories')->find($id);
// Or better, Laravel throws a 404 error when the id doesn't exists
$variant = Variant::with('categories')->findOrFail($id);

Laravel 5.7-未定义偏移量：1

1 个答案: