using System;

using System.Collections.Generic;

using System.Linq;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

​

public class Program

{

    public static void Main()

    {

        string input = @"{

    ""result"": ""success"",

    ""totalresults"": ""100"",

    ""items"": {

        ""item"": [            

            {

                ""id"": ""5812"",                

                ""lineitems"": {

                    ""lineitem"": [

                        {

                            ""type"": ""product"",                            

                            ""status"": ""Active""

                        }

                    ]

                }

            },

            {

                ""id"": ""5"",               

                ""lineitems"": []

            }

          ]

    }

}";

​

        var result = JsonConvert.DeserializeObject<Root>(input);

        result.Dump();

    }

    public partial class Root

    {

        [JsonProperty("result")]

        public string Result { get; set; }

​

        [JsonProperty("totalresults")]

        public string Totalresults { get; set; }

​

        [JsonProperty("items")]

        public Items Items { get; set; }

    }

​

    public partial class Items

    {

        [JsonProperty("item")]

        public List<Item> Item { get; set; }

    }

​

    public partial class Item

    {

        [JsonProperty("id")]

        public string Id { get; set; }

​

        [JsonProperty("lineitems")]     

        [JsonConverter(typeof(SingleOrArrayConverter<ItemLineitem>))]

        public List<ItemLineitem> Lineitems { get; set; }

    }

​

    public partial class ItemLineitem

    {

        [JsonProperty("lineitem")]

        public List<LineitemLineitem> Lineitem { get; set; }

    }

​

    public partial class LineitemLineitem

    {

        [JsonProperty("type")]

        public string Type { get; set; }

​

        [JsonProperty("status")]

        public string Status { get; set; }

    }

    class SingleOrArrayConverter<T> : JsonConverter

    {

        public override bool CanConvert(Type objectType)

        {

            return (objectType == typeof(List<T>));

        }

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

        {

            JToken token = JToken.Load(reader);

            if (token.Type == JTokenType.Array)

            {

                return token.ToObject<List<T>>();

            }

            return new List<T> { token.ToObject<T>() };

        }

​

        public override bool CanWrite

        {

            get { return false; }

        }

​

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

    }

​

}