Sample ContractResolver that conditionally removes properties from JSON. This can be plumbed into ASP.NET/API

ShouldSerializeContractResolver.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Linq
{
    using AutoMapper;
    using Newtonsoft.Json;
    using Newtonsoft.Json.Serialization;
    using System.Reflection;

    class Program
    {
        static void Main(string[] args)
        {
            Mapper.CreateMap<Person, Member>()
                .ForMember(dest => dest.dob, opt => opt.MapFrom(src => src.Age));
            //.ForMember(dest => dest.Age, opt => opt.Condition(src => (src.Age >= 20)));
            //.ForMember(c => c.FirstName, option => option.Ignore());

            var s = new ShouldSerializeContractResolver();

            var p = new Person() { 
                FirstName = "Garry", Surname = "Taylor", Age = 19,
                isMaxLoan = true, isMaxValuation = false, isMinLoan = false, isMinValuation = true
            };

            Member dto = Mapper.Map<Member>(p);

            var memberJson = Newtonsoft.Json.JsonConvert.SerializeObject(dto,
                new JsonSerializerSettings { ContractResolver = new ShouldSerializeContractResolver() });

            Console.WriteLine(memberJson);
            Console.ReadLine();

        }
    }

    class Person
    {
        public String FirstName { get; set; }
        public String Surname { get; set; }
        public int Age { get; set; }
        public bool? isMinLoan { get; set; }
        public bool? isMaxLoan { get; set; }
        public bool? isMinValuation { get; set; }
        public bool? isMaxValuation { get; set; }
    }

    class Member
    {
        public String FirstName { get; set; }
        public String Surname { get; set; }
        public int? dob { get; set; }
        [JsonIgnore]
        public String fullname { get; set; }
        public bool? isMinLoan { get; set; }
        public bool? isMaxLoan { get; set; }
        public bool? isMinValuation { get; set; }
        public bool? isMaxValuation { get; set; }
    }

    public class ShouldSerializeContractResolver : DefaultContractResolver
    {
        public new static readonly ShouldSerializeContractResolver Instance = new ShouldSerializeContractResolver();

        protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
        {
            JsonProperty property = base.CreateProperty(member, memberSerialization);

            if (property.DeclaringType == typeof(Member) && property.PropertyName.StartsWith("is"))
            {
                property.ShouldSerialize =
                    instance =>
                    {
                        Member e = (Member)instance;

                        var value = (bool?) e.GetType().GetProperty(property.PropertyName).GetValue(e, null);
                        
                        return value == false;
                    };
            }

            return property;
        }
    }

}