How can I tell the MongoDB C# driver to store all Guids in string format?

Question

I'm currently applying the [BsonRepresentation(BsonType.String)] attribute to all Guid properties in my domain models to have those properties serialized in string format. Besides being tiresome to do, that doesn't work out sometimes, e.g. with custom Wrapper<T> classes:

public class Wrapper<T>
{
    public T Value { get; set; }

    // Further properties / business logic ...
}

When T is Guid, the Value property will be stored as binary data of type UuidLegacy (as will any property of type Guid that's not decorated with the above attribute). However, I'd like all Guids, including Wrapper<Guid>.Value, to be represented as a string in the database.

Is there any way to tell the MongoDB C# driver to store all Guids in string format?

Answer 1

This can be achieved using Conventions

Something along the lines of:

var myConventions = new ConventionProfile();
myConventions.SetSerializationOptionsConvention(
    new TypeRepresentationSerializationOptionsConvention(typeof (Guid), BsonType.String));

BsonClassMap.RegisterConventions(myConventions, t => t == typeof (MyClass));

This should go somewhere in your app startup.

You can read more about conventions here: http://www.mongodb.org/display/DOCS/CSharp+Driver+Serialization+Tutorial#CSharpDriverSerializationTutorial-Conventions