private MongoDB.Bson.BsonDocument Swap(MongoDB.Bson.BsonDocument _doc) { var keys = JsonConvert.DeserializeObject <List <SwapKeyValue> >(this.SwapKeyValues); foreach (SwapKeyValue skv in keys) { MongoDB.Bson.BsonElement v = new MongoDB.Bson.BsonElement(); if (_doc.TryGetElement(skv.Source, out v)) { _doc.Add(new MongoDB.Bson.BsonElement(skv.Destination, _doc[skv.Source])); _doc.Remove(skv.Source); } } return(_doc); }