Custom validation unique property - generic classes

Question

I\'m trying to make a custom validation [IsUnique]. That check if is property value is unique and return a proper message.

This is my code, but this only work for a spec

Answer 1

I think the best way is to let the database do its works.

Create a constraint in the database to prevent two articles have the same name (or whatever uniqueness you need). Then, when the user create a new article or update an existing one with an existing article name, the database will throw an exception. Catch that exception and let the user knows about the issue.