在我的情况下使用扩展方法是否正确？

I use MVC4 and entity framework 5 in my project and I've lots of tables. As a rule of our project, we don't delete any records from database, each record has a isActive field and if that field is false, then we consider it deleted. I wanted to write an extension method to get active records and after some googling I wrote this:I use MVC4 and entity framework 5 in my project