using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;

​

    public static class JsonExtensions

    {

        public static IEnumerable<JToken> AncestorsAndSelf(this JToken token) // dotnetfiddle.net seems to be loading Json.NET 6.0 not 7.0.  This extension method is not needed in 7.0 

        {

            for (JToken current = token; current != null; current = current.Parent)

            {

                yield return current;

            }

        }

        public static void MoveTo(this JToken token, JObject newParent)

        {

            if (newParent == null)

                throw new ArgumentNullException();

            var toMove = AncestorsAndSelf(token).OfType<JProperty>().First(); // Throws an exception if no parent property found.

            if (toMove.Parent != null)

                toMove.Remove();

            newParent.Add(toMove);

        }

    }

​

    public static class RecursiveEnumerableExtensions

    {

        static bool ContainsNonNullKey<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, TKey key)

        {

            if (dictionary == null)

                throw new ArgumentNullException();

            return key == null ? false : dictionary.ContainsKey(key); // Dictionary<int?, X> throws on ContainsKey(null, ...)

        }

​

        public static IEnumerable<TResult> ToTree<TInput, TKey, TResult>(

            this IEnumerable<TInput> collection,

            Func<TInput, TKey> idSelector,

            Func<TInput, TKey> parentIdSelector,

            Func<TInput, TResult> nodeSelector,

            Action<TResult, TResult> addMethod)

        {

            if (collection == null || idSelector == null || parentIdSelector == null || nodeSelector == null || addMethod == null)

                throw new ArgumentNullException();

            var list = collection.ToList(); // Prevent multiple enumerations of the incoming enumerable.

            var dict = list.ToDictionary(i => idSelector(i), i => nodeSelector(i));

            foreach (var input in list.Where(i => dict.ContainsNonNullKey(parentIdSelector(i))))

            {

                addMethod(dict[parentIdSelector(input)], dict[idSelector(input)]);

            }

            return list.Where(i => !dict.ContainsNonNullKey(parentIdSelector(i))).Select(i => dict[idSelector(i)]);

        }

    }

​

    public partial class MenuItem

    {

        public int SiteMenuId { get; set; }

        public int SiteId { get; set; }

        public string MenuName { get; set; }

        public string Url { get; set; }

        public Nullable<int> ParentId { get; set; }

        public int CreatedUser { get; set; }

        public System.DateTime CreatedDate { get; set; }

        public Nullable<int> ModifiedUser { get; set; }

        public Nullable<System.DateTime> ModifiedDate { get; set; }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var desiredJson = @"{

                ""Menu"": {

                    ""aaa"": ""aaa"",

                    ""bbb"": {

                        ""ccc"": ""ccc"",

                        ""ddd"": ""ddd""

                    },

                    ""eee"": ""eee""

                }

            }";

​

            List<MenuItem> menuItems = new List<MenuItem>();

            menuItems.Add(new MenuItem() { SiteMenuId = 1, ParentId = null, MenuName = "Menu", Url = null, SiteId = 1 });

            menuItems.Add(new MenuItem() { SiteMenuId = 2, ParentId = 1, MenuName = "aaa", Url = "aaa", SiteId = 1 });

            menuItems.Add(new MenuItem() { SiteMenuId = 3, ParentId = 1, MenuName = "bbb", Url = null, SiteId = 1 });

            menuItems.Add(new MenuItem() { SiteMenuId = 4, ParentId = 3, MenuName = "ccc", Url = "ccc", SiteId = 1 });

            menuItems.Add(new MenuItem() { SiteMenuId = 5, ParentId = 3, MenuName = "ddd", Url = "ddd", SiteId = 1 });

            menuItems.Add(new MenuItem() { SiteMenuId = 6, ParentId = 1, MenuName = "eee", Url = "eee", SiteId = 1 });

​

            var json = CreateJsonFromMenuItems(menuItems);

​

            Console.WriteLine(json);

​

            if (!JToken.DeepEquals(JToken.Parse(json), JToken.Parse(desiredJson)))

                throw new InvalidOperationException();

        }

        public static string CreateJsonFromMenuItems(IList<MenuItem> menuItems)

        {

            return new JObject

            (

                menuItems.ToTree(

                    m => (int?)m.SiteMenuId,

                    m => m.ParentId, m => new JProperty(m.MenuName, m.Url),

                    (parent, child) =>

                    {

                        if (parent.Value == null || parent.Value.Type == JTokenType.Null)

                            parent.Value = new JObject();

                        else if (parent.Value.Type != JTokenType.Object)

                            throw new InvalidOperationException("MenuItem has both URL and children");

                        child.MoveTo((JObject)parent.Value);

                    })

            ).ToString();

        }

    }

​

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine(typeof(JToken).Assembly.FullName);

            Console.WriteLine("");

            TestClass.Test();

        }

    }