php 此集合实例上不存在属性 [title]
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Property [title] does not exist on this collection instance
提问by zkanoca
I am following Laracasts' videos: Basic Model/Controller/View Workflow.
我正在关注 Laracasts 的视频：Basic Model/Controller/View Workflow。
I have a table holds contact information.
我有一张桌子保存联系信息。
CREATE TABLE `about` (
`id` int(10) UNSIGNED NOT NULL,
`title` varchar(500) COLLATE utf8_unicode_ci NOT NULL,
`content` text COLLATE utf8_unicode_ci,
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci
I am trying to pass data to view using the following code in the controller file:
我正在尝试使用控制器文件中的以下代码将数据传递给视图：
public function index()
{
$about = Page::where('page', 'about-me')->get(); //id = 3
return view('about', compact('about'));
}
When I try to show the code as shown below,
当我尝试显示如下所示的代码时，
@section('title')
{{$about->title}}
@stop
@section('content')
{!! $about->content !!}
@stop
I get error that says:
我收到错误消息：
Property [title] does not exist on this collection instance. (View: E:\laragon\www\newsite\resources\views\about.blade.php)
此集合实例上不存在属性 [title]。（查看：E:\laragon\www\newsite\resources\views\about.blade.php）
But if I change the retrieving method in the controller file, it works.
但是如果我更改控制器文件中的检索方法，它就可以工作。
public function index()
{
$about = Page::find(3);
return view('about', compact('about'));
}
When I use dd($about)in the first case (where()->get()) the data is encapsulated by an array. In the second case (find(3)) it displays data as expected.
当我dd($about)在第一种情况 ( where()->get()) 中使用时，数据被一个数组封装。在第二种情况 ( find(3)) 中，它按预期显示数据。
What am i doing wrong?
我究竟做错了什么？
回答by Alexey Mezenin
When you're using get()you get a collection. In this case you need to iterate over it to get properties:
当您使用时，get()您会得到一个集合。在这种情况下，您需要对其进行迭代以获取属性：
@foreach ($collection as $object)
{{ $object->title }}
@endforeach
Or you could just get one of objects by it's index:
或者你可以通过它的索引获取一个对象：
{{ $collection[0]->title }}
Or get first object from collection:
或者从集合中获取第一个对象：
{{ $collection->first() }}
When you're using find()or first()you get an object, so you can get properties with simple:
当您使用find()或first()获得object 时，您可以通过简单的方式获得属性：
{{ $object->title }}
回答by Alex
With get()method you get a collection (all data that match the query), try to use first()instead, it return only one element, like this:
使用get()方法你得到一个集合（与查询匹配的所有数据），尝试使用first()它，它只返回一个元素，如下所示：
$about = Page::where('page', 'about-me')->first();
回答by Pnj Patel
You Should Used Collection keyword in Controller. Like Here..
您应该在 Controller 中使用 Collection 关键字。像这儿..
public function ApiView(){
return User::collection(Profile::all());
}
Here, User is Resource Name and Profile is Model Name. Thank You.
这里，用户是资源名称，配置文件是模型名称。谢谢你。
回答by Phantih
$about = DB::where('page', 'about-me')->first();
in stead ofget().
代替get().
It works on my project. Thanks.
它适用于我的项目。谢谢。
回答by Onyash Ed
$about->first()->idor
$stm->first()->titleand your problem is sorted out.
$about->first()->id或者
$stm->first()->title，您的问题已解决。
回答by agm1984
A person might get this while working with factory functions, so I can confirm this is valid syntax:
一个人在使用工厂函数时可能会得到这个，所以我可以确认这是有效的语法：
$user = factory(User::class, 1)->create()->first();
You might see the collection instance error if you do something like:
如果您执行以下操作，您可能会看到集合实例错误：
$user = factory(User::class, 1)->create()->id;
so change it to:
所以将其更改为：
$user = factory(User::class, 1)->create()->first()->id;
