Dto.cs

    public interface IMyBriefDto
    {
        public string Name { get; set; }
        public string Address { get; set; }
    }

    public interface IMyDto : IMyBriefDto
    {
        public int Age { get; set; }
        public string Country { get; set; }
    }

    public interface IListItem
    {
        string Id { get; }
    }

    public interface IMyListItem : IMyBriefDto, IListItem
    {
    }

    [DataContract]
    class MyDto : IMyDto, IMyListItem
    {
        [DataMember]
        public string Id => Name;
        [DataMember]
        public string Name { get; set; }
        [DataMember]
        public string Address { get; set; }
        [DataMember]
        public int Age { get; set; }
        [DataMember]
        public string Country { get; set; }
    }

    [AllowAnonymous]
    [Route("admin/sample")]
    public class SampleController : ControllerBase
    {
        [HttpGet("list.json")]
        public IMyBriefDto[] GetListItems()
        {
            return new IMyBriefDto[]
            {
                new MyDto() {Name = "Andrey", Address = "Andrey Address"},
                new MyDto() {Name = "Maxim", Address = "Maxim Address"},
                new MyDto() {Name = "Sergey", Address = "Sergey Address"},
            };
        }

        [HttpGet("{id}")]
        public IMyDto GetMyDto([FromRoute] string id)
        {
            return id switch
            {
                "Andrey" => new MyDto() {Name = "Andrey", Address = "Andrey Address", Age = 35, Country = "Russia"},
                "Maxim" => new MyDto() {Name = "Andrey", Address = "Andrey Address", Age = 35, Country = "Russia"},
                "Sergey" => new MyDto() {Name = "Andrey", Address = "Andrey Address", Age = 35, Country = "Russia"},
                _ => throw new Exception("Unknown dto")
            };
        }
    }