It is possible to use value objects (VOs) in MongoDB.
To generate a converter (serializer), add the Bson conversion in the attribute, e.g.
[ValueObject<string>(conversions: Conversions.Bson)]
public partial class Name
{
public static readonly Name NotSet = new("[NOT_SET]");
}
Now that the serializers are generated, you now need to register them.
Vogen generates a static class named RegisterBsonSerializersFor[NameOfProject].
This static class has a static method named TryRegister, which registers the serializers if they’re not already registered, e.g.:
BsonSerializer.TryRegisterSerializer(new CustomerIdBsonSerializer());
BsonSerializer.TryRegisterSerializer(new EnergyUsedBsonSerializer());
A MongoDB example is included in the source.
Below is a walkthrough of that sample.
The sample uses MongoDB to read and write entities (a Person) to a MongoDB database in a testcontainer.
Note that attributes on the value objects do not specify the BSON serializer; that is specified in global config in ModuleInitializer.cs:
[ValueObject]
public readonly partial struct Age;
[ValueObject<string>]
public readonly partial struct Name;
public class Person
{
public Name Name { get; set; }
public Age Age { get; set; }
}
This simple example registers the serializers manually:
BsonSerializer.RegisterSerializer(new NameBsonSerializer());
BsonSerializer.RegisterSerializer(new AgeBsonSerializer());
… but it could just as easily registered them with the generated register:
BsonSerializationRegisterForVogen_Examples.TryRegister();
(replace Vogen_Examples with the name of your project)
Next, it adds a bunch of Person objects to the database, each containing value objects representing age and name, and then reads them back.
