Laravel excel library(Maatwebsite) : How to create a drop down list in exports

  public function index() {        \Excel::create('file', function($excel) {            require_once("/apppath//vendor/phpoffice/phpexcel/Classes/PHPExcel/NamedRange.php");            require_once("/apppath/vendor/phpoffice/phpexcel/Classes/PHPExcel/Cell/DataValidation.php");            $excel->sheet('New sheet', function($sheet) {                $sheet->SetCellValue("A1", "UK");                $sheet->SetCellValue("A2", "USA");                $sheet->_parent->addNamedRange(                        new \PHPExcel_NamedRange(                        'countries', $sheet, 'A1:A2'                        )                );                $sheet->SetCellValue("B1", "London");                $sheet->SetCellValue("B2", "Birmingham");                $sheet->SetCellValue("B3", "Leeds");                $sheet->_parent->addNamedRange(                        new \PHPExcel_NamedRange(                        'UK', $sheet, 'B1:B3'                        )                );                $sheet->SetCellValue("C1", "Atlanta");                $sheet->SetCellValue("C2", "New York");                $sheet->SetCellValue("C3", "Los Angeles");                $sheet->_parent->addNamedRange(                        new \PHPExcel_NamedRange(                        'USA', $sheet, 'C1:C3'                        )                );                $objValidation = $sheet->getCell('D1')->getDataValidation();                $objValidation->setType(\PHPExcel_Cell_DataValidation::TYPE_LIST);                $objValidation->setErrorStyle(\PHPExcel_Cell_DataValidation::STYLE_INFORMATION);                $objValidation->setAllowBlank(false);                $objValidation->setShowInputMessage(true);                $objValidation->setShowErrorMessage(true);                $objValidation->setShowDropDown(true);                $objValidation->setErrorTitle('Input error');                $objValidation->setError('Value is not in list.');                $objValidation->setPromptTitle('Pick from list');                $objValidation->setPrompt('Please pick a value from the drop-down list.');                $objValidation->setFormula1('countries'); //note this!            });        })->download("xlsx");        return view('home');    }

for maatwebite version V.3.1 use below code

<?phpnamespace App\Exports;use App\Models\Category;use Illuminate\Contracts\View\View;use Maatwebsite\Excel\Concerns\FromView;use Maatwebsite\Excel\Concerns\WithEvents;use Maatwebsite\Excel\Concerns\WithTitle;use Maatwebsite\Excel\Events\AfterSheet;use PhpOffice\PhpSpreadsheet\Cell\DataValidation;class BulkUploadProductExport implements FromView, WithEvents , WithTitle{      public function view(): View    {        return view('exports', [            'categories' => Category::all()        ]);    }    public function title(): string    {        return 'bulkupload';    }    public function registerEvents(): array    {        //$event = $this->getEvent();        return [            AfterSheet::class => function (AfterSheet $event) {                               /** @var Sheet $sheet */                $sheet = $event->sheet;                /**                 * validation for bulkuploadsheet                 */                $sheet->setCellValue('B5', "SELECT ITEM");                $configs = "DUS800, DUG900+3xRRUS, DUW2100, 2xMU, SIU, DUS800+3xRRUS, DUG900+3xRRUS, DUW2100";                $objValidation = $sheet->getCell('B5')->getDataValidation();                $objValidation->setType(DataValidation::TYPE_LIST);                $objValidation->setErrorStyle(DataValidation::STYLE_INFORMATION);                $objValidation->setAllowBlank(false);                $objValidation->setShowInputMessage(true);                $objValidation->setShowErrorMessage(true);                $objValidation->setShowDropDown(true);                $objValidation->setErrorTitle('Input error');                $objValidation->setError('Value is not in list.');                $objValidation->setPromptTitle('Pick from list');                $objValidation->setPrompt('Please pick a value from the drop-down list.');                $objValidation->setFormula1('"' . $configs . '"');                          }        ];    }}