using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

// https://stackoverflow.com/questions/33616005/get-a-list-of-json-property-names-from-a-class-to-use-in-a-query-string/33616653#33616653

​

    public class model

    {

        [JsonProperty(PropertyName = "id")]

        public long ID { get; set; }

        [JsonProperty(PropertyName = "some_string")]

        public string SomeString { get; set; }

        public string Foo { get; set; }

​

        [JsonProperty]

        string Bar { get; set; }

​

        [JsonIgnore]

        public string IgnoreMe { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            // Allocate the relevant contract resolver. 

            // Options are CamelCasePropertyNamesContractResolver() or DefaultContractResolver().

            IContractResolver resolver = new DefaultContractResolver(); 

​

            // Get properties

            var propertyNames = resolver.PropertyNames(typeof(model));

            var fields = "&fields=" + String.Join(",", propertyNames);

​

            Console.WriteLine(fields);

            Assert.IsTrue(fields == @"&fields=id,some_string,Foo,Bar");

        }

    }

​

    public static class JsonExtensions

    {

        public static string [] PropertyNames(this IContractResolver resolver, Type type)

        {

            if (resolver == null || type == null)

                throw new ArgumentNullException();

            var contract = resolver.ResolveContract(type) as JsonObjectContract;

            if (contract == null)

                return new string[0];

            return contract.Properties.Where(p => !p.Ignored).Select(p => p.PropertyName).ToArray();

        }

    }

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: " + Environment.Version);

            Console.WriteLine("Json.NET version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​

    public class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

​