c# mongodb drive IngoreExtraElements and RegisterClassMap

        private static void RegisterClassMaps(IEnumerable<Type> clrTypes)
        {
            foreach (var clrType in clrTypes)
            {
                if (clrTypes.Any(x => x.BaseType.Name == clrType.Name))
                {
                    var genericSetIsRootClassMethod = MongoDBDataServiceFactorySetIsRootClassMethod.MakeGenericMethod(clrType);
                    var genericBsonClassMap = typeof(BsonClassMap<>).MakeGenericType(clrType);
                    var actionT = typeof(Action<>).MakeGenericType(genericBsonClassMap);
                    var @delegate = Delegate.CreateDelegate(actionT, genericSetIsRootClassMethod);

                    RegisterClassMapWithExpressionMethod.MakeGenericMethod(clrType).Invoke(typeof(BsonClassMap), new object[] { @delegate });
                }
                else
                {
                    RegisterClassMapWithoutExpressionMethod.MakeGenericMethod(clrType).Invoke(typeof(BsonClassMap), new object[] { });
                }
            }
        }

        private static void SetIsRootClass<T>(BsonClassMap<T> map)
        {
            map.SetIsRootClass(true);
        }

        // 忽略未绑定字段, 例如 mongodb 自带的 _id，否则查询时反序列化会报错，提示在 type 中找不到 _id 字段
        private static void IgnoreExtraElements()
        {
            var pack = new ConventionPack
            {
                new IgnoreExtraElementsConvention(true)
            };
            ConventionRegistry.Register("My Solution Conventions", pack, t => true);
        }

        private static readonly MethodInfo RegisterClassMapWithExpressionMethod = typeof(BsonClassMap).GetMethods().Where(x => x.Name == nameof(BsonClassMap.RegisterClassMap)).ToList()[1];
        private static readonly MethodInfo RegisterClassMapWithoutExpressionMethod = typeof(BsonClassMap).GetMethods().First(x => x.Name == nameof(BsonClassMap.RegisterClassMap));
        private static readonly MethodInfo MongoDBDataServiceFactorySetIsRootClassMethod = typeof(MongoDBDataServiceFactory).GetMethod(nameof(MongoDBDataServiceFactory.SetIsRootClass), BindingFlags.NonPublic | BindingFlags.Static);