优化下拉列表组件，修复若干BUG

app/admin/controller/mall/User.php

@@ -45,8 +45,7 @@ class User extends Backend
         }
 
         if ($request->get('select') || $request->post('select')) {
-            $this->_select();
-            return $this->success();
+            return $this->select($request);
         }
 
         list($where, $alias, $limit, $order) = $this->queryBuilder();
@@ -182,6 +181,32 @@ class User extends Backend
         return $this->success('', ['row' => $row]);
     }
 
+    /**
+     * 远程下拉数据（供 remoteSelect 使用）
+     */
+    public function select(Request $request): Response
+    {
+        $response = $this->initializeBackend($request);
+        if ($response !== null) {
+            return $response;
+        }
+
+        list($where, $alias, $limit, $order) = $this->queryBuilder();
+        $res = $this->model
+            ->withoutField('password')
+            ->withJoin($this->withJoinTable, $this->withJoinType)
+            ->visible(['admin' => ['username']])
+            ->alias($alias)
+            ->where($where)
+            ->order($order)
+            ->paginate($limit);
+
+        return $this->success('', [
+            'list'  => $res->items(),
+            'total' => $res->total(),
+        ]);
+    }
+
     /**
      * 删除
      */