public class FormViewModel
        {
            [HiddenInput] public Guid Id { get; set; }

            [Required]
            [StringLength(128, MinimumLength = 4)]
            public string Name { get; set; }

            [DataType(DataType.Password)] public string Password { get; set; }
            public string PhoneNumber { get; set; }

            [Required] public int Age { get; set; }
            [DisplayOrder(20000)] public bool Confirm { get; set; }

            [Display(Name = "BirthDay")]
            [DataType(DataType.Date)]
            public DateTime BirthDateTime { get; set; }

            public DateTime UpdateDateTime { get; set; }
            public CarType CarType { get; set; }
            [RadioGroup(4)] public CarType CarType2 { get; set; }
            [CheckboxGroup(2)] public List<CarType> CarType3 { get; set; }
            [SelectItems(nameof(CountryList))] public string Country { get; set; }

            [SelectItems(nameof(CityList))] public List<string> City { get; set; }

            [SelectItems(nameof(CityList))]
            [CheckboxGroup(4)]
            public List<string> City1 { get; set; }

            [TagInput(5)] public List<string> Tags { get; set; }
            public string[] Tags2 { get; set; }

            [TextArea] public string Remarks { get; set; }
            public Address Address { get; set; }
        }

        public class Address
        {
            public string Street { get; set; }
            public string City { get; set; }
            public string Postcode { get; set; }
            public string Country { get; set; }
        }

        

        
        public class FormViewModel
        {
            ...

            [FormContentGroup("base")]
            [DataType(DataType.Password)] 
            public string Password { get; set; }

            ...
        }

        public class Address
        {
            [FormContentGroup("address")] public string Street { get; set; }
            [FormContentGroup("address")] public string City { get; set; }
            [FormContentGroup("address")] public string Postcode { get; set; }
            [FormContentGroup("address")] public string Country { get; set; }
        }