您是否在寻找错误消息的解释？

它表示你的模型不再是底层数据库，你必须更新它（数据库）...

可能你在模型中添加了一些字段但没有反映那些数据库中的字段...

该错误还建议在VS内部使用工具进行更新...

Are you looking for an explanation to the error message?
It says that your model do not mach anymore the underlying database and you have to update it (the database)...
Probably you added some fields to the model but did not reflected those fields in the database...
The error also suggest a tool to use from inside VS to do the update...