You can do it from Visual Studio during debugging without writing any code, not even a catch block.
Just add a watch with the name:
((System.Data.Entity.Validation.DbEntityValidationException)$exception).EntityValidationErrors
The watch expression $exception displays any exception thrown in the current context, even if it has not been caught and assigned to a variable.
Based on http://mattrandle.me/viewing-entityvalidationerrors-in-visual-studio/
