增加$form->fields判断，orderBy id desc

app/AdminSupplier/Controllers/DiyFormController.php

@@ -22,7 +22,7 @@ class DiyFormController extends AdminController
         return Grid::make(new DiyForm(['fields']), function (Grid $grid) {
 			$grid->disableViewButton();
 
-        	$grid->model()->where('supplier_id', Admin::user()->id);
+        	$grid->model()->where('supplier_id', Admin::user()->id)->orderBy('id', 'desc');
 
             $grid->column('id')->sortable();
             $grid->column('name');
@@ -108,6 +108,10 @@ class DiyFormController extends AdminController
 				return $form->response()->error('数据不存在');
 			}
 
+			if (!$form->fields) {
+				return $form->response()->error('字段为空，请先新增字段');
+			}
+
 			$form->hidden(['supplier_id']);
 			$form->supplier_id = Admin::user()->id;
 		})->deleting(function (Form $form) {