创建和修改的MVC 3日期在SQL Server 2008 R2中具有默认值和触发器，但仍然需要值

I have generated classes (DbContext) modelling my db (SQL Server 2008 R2), and in most of my tables I have the standard ModifiedDate and CreatedDate (No Nulls). Each of these has a default of getdate() in SQLServer, and I have a trigger to update ModifiedDate on any updates.I have generated classes (DbContext) modelling