MongoDB.Bson.Serialization.Serializers.DictionarySerializer.Deserialize C# (CSharp) Метод

        public override object Deserialize(
            BsonReader bsonReader,
            Type nominalType,
            Type actualType,
            IBsonSerializationOptions options)
        {
            var dictionarySerializationOptions = EnsureSerializationOptions(options);
	        var keyValuePairSerializationOptions = dictionarySerializationOptions.KeyValuePairSerializationOptions;

            var bsonType = bsonReader.GetCurrentBsonType();
            if (bsonType == BsonType.Null)
            {
                bsonReader.ReadNull();
                return null;
            }
            else if (bsonType == BsonType.Document)
            {
                if (nominalType == typeof(object))
                {
                    bsonReader.ReadStartDocument();
                    bsonReader.ReadString("_t"); // skip over discriminator
                    bsonReader.ReadName("_v");
                    var value = Deserialize(bsonReader, actualType, options); // recursive call replacing nominalType with actualType
                    bsonReader.ReadEndDocument();
                    return value;
                }

                var dictionary = CreateInstance(actualType);
                var valueDiscriminatorConvention = BsonSerializer.LookupDiscriminatorConvention(typeof(object));

                bsonReader.ReadStartDocument();
                while (bsonReader.ReadBsonType() != BsonType.EndOfDocument)
                {
                    var key = bsonReader.ReadName();
                    var valueType = valueDiscriminatorConvention.GetActualType(bsonReader, typeof(object));
                    var valueSerializer = BsonSerializer.LookupSerializer(valueType);
                    var value = valueSerializer.Deserialize(bsonReader, typeof(object), valueType, keyValuePairSerializationOptions.ValueSerializationOptions);
                    dictionary.Add(key, value);
                }
                bsonReader.ReadEndDocument();

                return dictionary;
            }
            else if (bsonType == BsonType.Array)
            {
                var dictionary = CreateInstance(actualType);

                bsonReader.ReadStartArray();
                while (bsonReader.ReadBsonType() != BsonType.EndOfDocument)
                {
                    var keyValuePair = (KeyValuePair<object, object>)_keyValuePairSerializer.Deserialize(
                        bsonReader,
                        typeof(KeyValuePair<object, object>),
                        keyValuePairSerializationOptions);
                    dictionary.Add(keyValuePair.Key, keyValuePair.Value);
                }
                bsonReader.ReadEndArray();

                return dictionary;
            }
            else
            {
                var message = string.Format("Can't deserialize a {0} from BsonType {1}.", nominalType.FullName, bsonType);
                throw new Exception(message);
            }
        }