我找不到原因......但我無法獲得我的 var 和任何其他. 函數實際上保存數據并驗證正常，然后也將新數據發送回編輯視圖，但我無法訪問我的 $success 變量...CourseController@update:class CourseController extends Controller {    public function update( Request $request, Course $course ) {        // Validates data or return to view with errors        $request->validate( Course::$validation_rules );        // Pass: Gets the record from db or returns 404        $course = Course::findOrFail( $course->id );        // Update the course        $course->name = Str::ucfirst( $request->name );        $course->description = Str::ucfirst( $request->description );        // Save the data        $course->save();        // Redirect to view with success        return redirect()->route( 'courses.edit', $course )            ->with( 'success', 'Cambios guardados.' ) // problem here? where?        ;    }}Course (model):class Course extends Model {    public static $validation_rules = [        'name' => 'required',        'description' => 'required'    ];}edit.blade.php (portion):{{-- some code before --}}    @if ( $errors->any() )        @foreach ( $errors->all() as $error )            <div class="alert alert-danger alert-dismissible fade show" role="alert">                <strong class="d-block"> {{ $error }} </strong>                <button type="button" class="close" data-dismiss="alert" aria-label="Close">                    <span aria-hidden="true">&times;</span>                </button>            </div>        @endforeach    @elseif ( $success ?? false )        <div class="alert alert-success alert-dismissible fade show" role="alert">            <strong>{{ $success }}</strong>            <button type="button" class="close" data-dismiss="alert" aria-label="Close">            <span aria-hidden="true">&times;</span>            </button>        </div>    @endif{{-- some code after --}}這就是我目前所擁有的。這非常奇怪，我總是從中得到 null$success以及我嘗試的任何其他......