php – 为什么我在Laravel视图中获得“Undefined variable”？

$posts变量工作正常.

@if(count($posts))

@foreach($posts as $post)
    @if($post->category)
        <div class="{{ $post->category->name }} isotope-item">
                <img src="../img/showcase/1.jpg" alt="">
                <div class="disp-post">
                    <span class="icon"></span>
                    <p class="time">{{ $post->updated_at }}</p>
                    <h4>{{ Str::words($post->title,3) }}</h4>
                    <p>{{ Str::words($post->body,60) }}</p>
                    <p class="link">{{ HTML::linkRoute('posts.show','Read more',array($post->id)) }}</p>
                 </div>
        </div>
    @endif
@endforeach
@endif

但是当我尝试$category时：

@if(count($category))
    @foreach($category as $c)
        <li><a href="#" data-filter="{{ $c->name }}">Networking</a></li>
    @endforeach
@endif

我收到一个错误.

我究竟做错了什么？

这是我的PostsController

public function showcase()
{
    $category = Category::all();
    $posts = Post::with('category')->orderBy('updated_at')->get();
    return View::make('posts.showcase',compact('posts'));
}