尝试阅读属性“ id”在布尔。但只有编辑形式

Question

我想在编辑表单中添加下拉 input input ，其中包含来自表（类）的选项，因此我使用foreach。当我只有输入表单时，它可以正常工作，但是当我添加编辑表单时，它会出现错误。我不明白为什么。请帮忙，我是Laravel的新手。

这是我的 输入表单 （我也想制作这样的编辑表格，并具有相同的输入和下拉列表）

这是我的代码。

视图

    <!-- INPUT FORM (MODAL) -->
<form method="post" action="{{ url('/grade/create') }}">
    @csrf
    <div class="row">
        <div class="form-group col-md-8 mb-3">
            <label>SNum</label>
            <input type="text" pattern="M+[0-9]{7,}" minlength="8" maxlength="8" class="form-control" name="SNum"
                required="required" />
        </div>
        <div class="form-group col-md-4 mb-3">
            <label>Class</label>
            <select class="form-select" name="class[]">
                {{-- Works fine --}}
                @foreach ($class as $class)
                    <option value="{{ $class->id }}">{{ $class->class }}</option>
                @endforeach
            </select>
        </div>
    </div>
</form>

@foreach ($grades as $grade)
    <!-- EDIT FORM (MODAL) -->
    <form method="post" action="{{ url('/grade/update' . $grade->id) }}">
        @csrf
        <div class="row">
            <div class="form-group col-md-8 mb-3">
                <label>SNum</label>
                <input type="text" value="{{ $grade->SNum }}" pattern="M+[0-9]{7,}" minlength="8"
                    maxlength="8" class="form-control" name="SNum" required="required" />
            </div>
            <div class="form-group col-md-4 mb-3">
                <label>Class</label>
                <select class="form-select" name="class[]" id="class{{ $grade->id }}">
                    @foreach ($class as $class)
                        {{-- Attempt to read property "id" on bool --}}
                        <option value="{{ $class->id }}">{{ $class->class }}</option>
                    @endforeach
                </select>
            </div>
        </div>
    </form>

    <div class="modal fade" id="deleteModal{{ $grade->id }}" tabindex="-1" role="dialog"
        aria-labelledby="exampleModalCenterTitle" aria-hidden="true">
        <div class="modal-dialog modal-dialog-centered" role="document">
            <div class="modal-content">
                <form method="post" action="{{ url('/grade/delete/' . $grade->id) }}">
                    @csrf
                    <div class="modal-body"
                        style="height:100px; display:flex; align-items:center; justify-content:center;">
                        <h5 class="text-center">Are you sure?</h5>
                    </div>
                    <div class="modal-footer">
                        <button type="submit" class="btn btn-danger">Ya</button>
                    </div>
                </form>
            </div>
        </div>
    </div>
@endforeach

控制器

<?php namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Models\Grade;
use App\Models\GradeClass;
use App\Models\Class;

class MainController extends Controller
{
    public function index()
    {
        $grades = Grade::get();
        $class = Class::get();
        return view('main', compact('grades', 'class'));
    }

    public function store(Request $request)
    {
        $request->validate([
            'SNum' => 'required|max:8|min:8',
            'class' => 'required'
        ]);

        $grade = Grade::create([
            'SNum' => $request['SNum']
        ]);

        if ($request->has('class')) {
            foreach ($request['class'] as $classId) {
                GradeClass::create([
                    'grades_id' => $grade->id,
                    'class_id' => (int) $classId,
                ]);
            }
        }

        return redirect('/')->with('status', 'Grade added!');
    }

    public function update(Request $request, Grade $grade)
    {
        $request->validate([
            'SNum' => 'required|max:8|min:8',
            'class' => 'required'
        ]);

        $grade->SNum = $request['SNum'];
        $grade->save();

        GradeClass::where('grades_id', $grade->id)->delete();

        if ($request->has('class')) {
            foreach ($request['class'] as $classId) {
                GradeClass::create([
                    'grades_id' => $grade->id,
                    'class_id' => (int) $classId,
                ]);
            }
        }
        return redirect('/')->with('status', 'Grade updated!');
    }
    public function destroy(Grade $grade)
    {
        GradeClass::where('grades_id', $grade->id)->delete();
        $grade->delete();

        return redirect('/')->with('status', 'Grade deleted!');
    }
}

路线

<?php
use Illuminate\Support\Facades\Route;
use App\Http\Controllers\MainController;

Route::get('/', [MainController::class, 'index']);
Route::controller(MainController::class)->prefix('grade')->name('grade.')->group(function () {
    Route::post('/create', 'store')->name('store');
    Route::post('/update/{grade}', 'update')->name('update');
    Route::post('/delete/{grade}', 'destroy')->name('destroy');
});

太感谢了！

Answer 1

尝试修复此问题：

@foreach ($class as $class)

即使有效，至少有一次，您在循环结束时销毁了原始$类变量，因此不再是您开始使用的对象。

修复您的代码，以便将结果数组传递给Blade作为变量名为$类的变量，以便您可以使用：

@foreach ($classes as $class)