In a RavenDB ASP.NET MVC app I was recently working on, I was constantly seeing good ol’ System.FormatException – “Input string was not in a correct format”.

My entities all use ints for their Ids.

After a while I noticed (via the RavenDB Management Console) that my entities had Ids like “tab/123”, but previously the Ids were like “tab-123”.

The problem turned out to be that I had accidentally removed this line while doing some refactoring:

documentStore.Conventions.IdentityPartsSeparator = "-";

Once I put that back in I stopped seeing the System.FormatException and all was right in the world.

I have a many to many relationship, like so

public class Movie
{
   public int Id { get; set; }
   public string Title { get; set; }
   public int[] ActorIds { get; set; }
   // etc
}

public class Actor
{
   public int Id { get; set; }
   public int Name { get; set; }
   // etc
}

When I load a Movie, I also want to load all of the Actors associated with that Movie.

This can be done using Raven’s Load<T>(IEnumerable<System.ValueType> ids) method, and casting the int[] to an array of ValueType, like so:

var movie = RavenSession.Load<Movie>(movieId);
var actorIds = movie.TabIds.Cast<System.ValueType>();

var actors = RavenSession.Load<Actor>(actorIds).OrderBy(x => x.Name);