Validate object based on external factors (ie. data store uniqueness)

Question

Description

My solution has these projects:

• DAL = Modified Entity Framework
• DTO = Data Transfer objects th

Answer 1

I had this exact same problem and after trying to find a work around for days and days and days, I ended up merging my DTO, DAL, and BL into one library. I kept my presentation layer separate. Not sure if that is an option for you or not. For me, I figured that my chances of ever changing the data store were very slight, and so the separate tier wasn't really needed.

I also have implemented the Microsoft Validation Application Block for all my DTO validations. They have a "Self Validation" method that lets you perform complex validations.