背景：
当我们在使用flask-admin进行WEB开发时应该第一时间想到的是竟可能使用框架推荐的modelView模型，其次才是自定义模型 baseview,因为只有modelview模型下开发才能最大限度的提高效率。
制作：
1、在modelview视图下框架会通过默认视图进行展示模型信息，有时候因业务需要在模型数据增改时需要做一些前置或者后置操作。
2、框架提供on_model_change和 after_model_change2个函数来分别应模型数据修改前和修改后事件
def after_model_change(self, form, model, is_created):
"""
Perform some actions after a model was created or updated and
committed to the database.
Called from create_model after successful database commit.
By default does nothing.
:param form:
Form used to create/update model
:param model:
Model that was created/updated
:param is_created:
True if model was created, False if model was updated
"""
pass
def on_model_change(self, form, model, is_created):
"""
Perform some actions before a model is created or updated.
Called from create_model and update_model in the same transaction
(if it has any meaning for a store backend).
By default does nothing.
:param form:
Form used to create/update model
:param model:
Model that will be created/updated
:param is_created:
Will be set to True if model was created and to False if edited
"""
pass
注意：a、2个函数的model中都可以拿到当前模型兑换ing表单form 信息和DB模型信息
b、这2个函数只能在modelview 模型及其子模型中生效