Using C# MongoDB Driver, how to serialize a collection of object referements?

BsonClassMap is not your solution, you should write your custom IBsonSerializer for B classI just implemeted the Serialize method, the Deserilze works same way.

public class BSerialzer : IBsonSerializer{    public object Deserialize(BsonReader bsonReader, Type nominalType, IBsonSerializationOptions options)    {        throw new NotImplementedException();    }    public object Deserialize(BsonReader bsonReader, Type nominalType, Type actualType, IBsonSerializationOptions options)    {        throw new NotImplementedException();    }    public IBsonSerializationOptions GetDefaultSerializationOptions()    {        throw new NotImplementedException();    }    public void Serialize(BsonWriter bsonWriter, Type nominalType, object value, IBsonSerializationOptions options)    {        var b = (B)value;        bsonWriter.WriteStartDocument();        bsonWriter.WriteString("_id", b.Id);                    bsonWriter.WriteStartArray("refs");        foreach (var refobj in b.ReferredAObjects)        {            bsonWriter.WriteString(refobj.Id);        }        bsonWriter.WriteEndArray();                    bsonWriter.WriteEndDocument();    }}

for a sample below objects

var a0 = new A{    Id = "0",    Name = "0",};var a1 = new A{    Id = "1",    Name = "1",};var b = new B{    Id = "b0",    ReferredAObjects = new Collection<A> { a0, a1 }};collection.Insert(b);

will produce output like:

{    "_id" : "b0",    "refs" : [         "0",         "1"    ]}

Just remember to register this Sterilizer at program start-up:

BsonSerializer.RegisterSerializer(typeof(B), new BSerialzer());