When you want to deserialize an object using an interface using this setup. It crashes with BsonSerializationException "No serializer found for type X". The way i have mongo setup is like this.

MongoRepository<TObject>
{
public MongoRepository(string serverUrl, string databaseName, MongoCredentials credentials)

{ var mongourl = new MongoUrl(serverUrl); _mongoServer = MongoServer.Create(mongourl); _mongoCollection = _mongoDatabase.GetCollection<TObject>(typeof(TObject).Name); }

public TObject Find(Expression<Func<TObject,bool>> predicate)

{ return _mongoCollection.AsQueryable().FirstOrDefault(predicate); }

}

When TObject is an Interface type it crashes with BsonSerializationException. A fix that works pretty well on git commit 6a30fd35ea2d45b3aa8f2c7b176a24e90980f150 in the BsonSerializer.cs file line 589 in the LookupSerializer method near where the exception is thrown i put this snippet in

if(serializer == null)
{
foreach (var bsonSerializer in __serializers)
{
if(type.IsAssignableFrom(bsonSerializer.Key))

{ serializer = bsonSerializer.Value; break; }

}
}

it will allow AsQueryable to use an interface type and deserialize it properly.