Laravel 视图文件中的未定义变量

Question

我在仪表板视图的 laravel 5.3.9 中收到一个错误，其中包含未定义的变量帖子。我正在尝试列出他在数据库中拥有的用户的所有帖子。到目前为止，这是我的代码：

UserController.php

<?php 

namespace App\Http\Controllers;

use App\User;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;


class UserController extends Controller 
{
    public function postSignUp(Request $request) 
    {   
        // Validate the entry of the sign up form
        $this->validate($request, [
            'email'      => 'email | required | unique:users',
            'first_name' => 'required | max:120',
            'password'   => 'required | min:6'
        ]);

        $email = $request['email'];
        $first_name = $request['first_name'];
        $password = bcrypt($request['password']);

        $user = new User();
        $user->email = $email;
        $user->first_name = $first_name;
        $user->password = $password;

        $user->save();

        Auth::attempt($user);

        return redirect()->route('dashboard');

    }

    public function postSignIn(Request $request) 
    {
        // Validate the sign in form
        $this->validate($request, [
            'email'      => 'email | required',
            'password'   => 'required | min:6'
        ]);

        if( Auth::attempt(['email' => $request['email'], 'password' => $request['password']]) ) {
            return view('dashboard');
        }

        return redirect()->back();
    }
}

?>

PostController.php

<?php 

namespace App\Http\Controllers;

use App\Post;
use Illuminate\Http\Request;

class PostController extends Controller 
{
    public function getDashboard()
    {
        $posts = Post::all();
        return view('dashboard', [ 'posts' => $posts ]);
    }

    public function postCreatePost(Request $request)
    {
        // Validate the post text field
        $this->validate($request, [
            'body' => 'required | max:1000'
        ]);

        $post = new Post();
        $post->body = $request['body'];
        $message  = "There was an error";

        if( $request->user()->posts()->save($post) ) {
            $message = "Post succesfully created";
        }
        return redirect()->route('dashboard')->with([ 'message' => $message ])->compact($posts);
    }

    public function getDeletePost($post_id) 
    {
        $post = Post::where('id', $post_id)->first();
        $post->delete();

        return redirect()->route('dashboard')->with(['message' => 'Post succesfully deleted']);
    }
}

dashboard.blade.php

@foreach($posts as $post)
        <article class="post">
            <p>{{ $post->body }}</p>
            <div class="info">
                Posted by {{ $post->user->first_name }} on {{ $post->user->created_at }}
            </div>
            <div class="interaction">
                <a href="#">Like</a> |
                <a href="#">Dislike</a> |
                <a href="#">Edit</a> |
                <a href="{{ route('post.delete', [ 'post_id' => $post->id ]) }}">Delete</a> 
            </div>
        </article>
        @endforeach

web.app 路线

    <?php

use App\Task;
use Illuminate\Http\Request;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| This file is where you may define all of the routes that are handled
| by your application. Just tell Laravel the URIs it should respond
| to using a Closure or controller method. Build something great!
|
*/

Route::group( ['middleware' => ['web']], function() 
{
    Route::get( '/', function () {
      return view('welcome');
    })->name('home');

    // Route for signed up users
    Route::post( '/signup', [
        'uses' => 'UserController@postSignUp',
        'as'   => 'signup'
    ]);

    // Redirect to signin
    Route::post( '/signin', [
        'uses' => 'UserController@postSignIn',
        'as'   => 'signin'
    ]);

    //Redirect to the dashboard
    Route::get('/dashboard', [
        'uses'       => 'PostController@getDashboard',
        'as'         => 'dashboard',
        'middleware' => 'auth'
    ]);

    // Create a new post and route
    Route::post('/createpost', [
        'uses' => 'PostController@postCreatePost',
        'as'   => 'post.create'
    ]);

    // Create a new post and route
    Route::get('/delete-post/{post_id}', [
        'uses'       => 'PostController@getDeletePost',
        'as'         => 'post.delete',
        'middleware' => 'auth'
    ]);

});

以及我得到的错误

    ErrorException in 3bda00b66abf627abd64dcb541751a9b753d4384.php line 33:
Undefined variable: posts (View: C:\wamp\www\laravel\resources\views\dashboard.blade.php)
    in 3bda00b66abf627abd64dcb541751a9b753d4384.php line 33
at CompilerEngine->handleViewException(object(ErrorException), '1') in PhpEngine.php line 44
at PhpEngine->evaluatePath('C:\wamp\www\laravel\storage\framework\views/3bda00b66abf627abd64dcb541751a9b753d4384.php', array('__env' => object(Factory), 'app' => object(Application), 'errors' => object(ViewErrorBag))) in CompilerEngine.php line 59
at CompilerEngine->get('C:\wamp\www\laravel\resources\views/dashboard.blade.php', array('__env' => object(Factory), 'app' => object(Application), 'errors' => object(ViewErrorBag))) in View.php line 150
at View->getContents() in View.php line 121
at View->renderContents() in View.php line 86
at View->render() in Response.php line 45
at Response->setContent(object(View)) in Response.php line 201
at Response->__construct(object(View)) in Router.php line 1042
at Router->prepareResponse(object(Request), object(View)) in Router.php line 642
at Router->Illuminate\Routing\{closure}(object(Request)) in Pipeline.php line 53
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in SubstituteBindings.php line 41
at SubstituteBindings->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in VerifyCsrfToken.php line 64
at VerifyCsrfToken->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in ShareErrorsFromSession.php line 49
at ShareErrorsFromSession->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in StartSession.php line 64
at StartSession->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in AddQueuedCookiesToResponse.php line 37
at AddQueuedCookiesToResponse->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in EncryptCookies.php line 59
at EncryptCookies->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in Pipeline.php line 104
at Pipeline->then(object(Closure)) in Router.php line 644
at Router->runRouteWithinStack(object(Route), object(Request)) in Router.php line 618
at Router->dispatchToRoute(object(Request)) in Router.php line 596
at Router->dispatch(object(Request)) in Kernel.php line 267
at Kernel->Illuminate\Foundation\Http\{closure}(object(Request)) in Pipeline.php line 53
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in CheckForMaintenanceMode.php line 46
at CheckForMaintenanceMode->handle(object(Request), object(Closure)) in Pipeline.php line 137
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Pipeline.php line 33
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in Pipeline.php line 104
at Pipeline->then(object(Closure)) in Kernel.php line 149
at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 116
at Kernel->handle(object(Request)) in index.php line 53

我不确定如何将 $posts 变量传递给视图文件。

Answer 1

如果 $posts 为空，您可能会遇到该错误。您可以尝试使用

封装 foreach

@if (isset($posts))
    @foreach ($posts as $post)
    ...
    @endforeach
@endif

Answer 2

您首先要在控制器上检查 $post 是否正在 returning 任何数据。所以就在这一行之后；

$posts = Post::all();

做一个

dd($posts);

如果这 return 有任何记录，那么您可以检查您的观点。正如@berkayk 的回答所述。您应该对您的视图进行一些检查，以确保您的视图不会引发错误或 return 通过检查控制器上的记录计数完全不同的视图。

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