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

        public override object Deserialize(
            BsonReader bsonReader,
            Type nominalType,
            Type actualType,
            IBsonSerializationOptions options)
        {
            VerifyTypes(nominalType, actualType, typeof(Version));

            BsonType bsonType = bsonReader.GetCurrentBsonType();
            string message;
            switch (bsonType)
            {
                case BsonType.Null:
                    bsonReader.ReadNull();
                    return null;
                case BsonType.Document:
                    bsonReader.ReadStartDocument();
                    int major = -1, minor = -1, build = -1, revision = -1;
                    while (bsonReader.ReadBsonType() != BsonType.EndOfDocument)
                    {
                        var name = bsonReader.ReadName();
                        switch (name)
                        {
                            case "Major": major = bsonReader.ReadInt32(); break;
                            case "Minor": minor = bsonReader.ReadInt32(); break;
                            case "Build": build = bsonReader.ReadInt32(); break;
                            case "Revision": revision = bsonReader.ReadInt32(); break;
                            default:
                                message = string.Format("Unrecognized element '{0}' while deserializing a Version value.", name);
                                throw new Exception(message);
                        }
                    }
                    bsonReader.ReadEndDocument();
                    if (major == -1)
                    {
                        message = string.Format("Version missing Major element.");
                        throw new Exception(message);
                    }
                    else if (minor == -1)
                    {
                        message = string.Format("Version missing Minor element.");
                        throw new Exception(message);
                    }
                    else if (build == -1)
                    {
                        return new Version(major, minor);
                    }
                    else if (revision == -1)
                    {
                        return new Version(major, minor, build);
                    }
                    else
                    {
                        return new Version(major, minor, build, revision);
                    }
                case BsonType.String:
                    return new Version(bsonReader.ReadString());
                default:
                    message = string.Format("Cannot deserialize Version from BsonType {0}.", bsonType);
                    throw new Exception(message);
            }
        }