account_book/app/Admin/Controllers/MerchantController.php

<?php

namespace App\Admin\Controllers;

use App\Models\MchApp;
use App\Models\Merchant;
use Dcat\Admin\Form;
use Dcat\Admin\Grid;
use Dcat\Admin\Show;
use Dcat\Admin\Http\Controllers\AdminController;

class MerchantController extends AdminController
{
    /**
     * Make a grid builder.
     *
     * @return Grid
     */
    protected function grid()
    {
        return Grid::make(new Merchant(), function (Grid $grid) {
            $grid->model()->orderBy('id', 'desc');

            $grid->column('id')->sortable();
            $grid->column('mch_no')->width('20%');
            $grid->column('mch_name')->width('28%');
            $grid->column('created_at');
            $grid->column('updated_at')->sortable();

            $grid->enableDialogCreate();
            $grid->showQuickEditButton();
            $grid->disableEditButton();

            $grid->filter(function (Grid\Filter $filter) {
                $filter->equal('mch_no')->width(3);
                $filter->like('mch_name')->width(3);
            });
        });
    }

    /**
     * Make a show builder.
     *
     * @param mixed $id
     *
     * @return Show
     */
    protected function detail($id)
    {
        return Show::make($id, new Merchant(), function (Show $show) {
            $show->field('id');
            $show->field('mch_no');
            $show->field('mch_name');
            $show->field('created_at');
            $show->field('updated_at');
        });
    }

    /**
     * Make a form builder.
     *
     * @return Form
     */
    protected function form()
    {
        return Form::make(new Merchant(), function (Form $form) {
            $form->display('id');

            if ($form->isCreating()) {
                $form->hidden('mch_no');
            } else {
                $form->display('mch_no');
            }

            $form->text('mch_name')->required();

            $form->display('created_at');
            $form->display('updated_at');

            $form->saving(function (Form $form) {
                if ($form->isCreating()) {
                    $form->mch_no = 'M'.time();
                }
            });

            $form->deleting(function (Form $form) {
                $data = $form->model()->toArray();
                foreach ($data as $k => $v) {
                    if (MchApp::where('mch_no', $v['mch_no'])->count() > 0) {
                        return $form->response()->error("商户号{$v['mch_no']}已创建应用，请先删除应用");
                    }
                }
            });
        });
    }
}