using Newtonsoft.Json;

using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var source = new List<TreeModel>

        {

            new TreeModel

            {

                ChangeFlowsFromParent = false,

                ChangeFlowsToParent = true,

                StreamType = "mainine",

                StreamName = "ArgOS_2_0",

                Parent = null,

                Compliance = "Released",

            },

            new TreeModel

            {

                ChangeFlowsFromParent = true,

                ChangeFlowsToParent = true,

                StreamType = "Release",

                StreamName = "ArgOS_2_0_DHAL1",

                Parent = "ArgOS_2_0",

                Compliance = "Released",

            },

            new TreeModel

            {

                ChangeFlowsFromParent = false,

                ChangeFlowsToParent = true,

                StreamType = "Release",

                StreamName = "ArgOS_2_0_child_DHAL2",

                Parent = "ArgOS_2_0_DHAL1",

                Compliance = "Released",

            },

            new TreeModel

            {

                ChangeFlowsFromParent = false,

                ChangeFlowsToParent = true,

                StreamType = "Release",

                StreamName = "ArgOS_child_Gen2",

                Parent = "ArgOS_2_0_child_DHAL2",

                Compliance = "Released",

            },

            new TreeModel

            {

                ChangeFlowsFromParent = true,

                ChangeFlowsToParent = true,

                StreamType = "Release",

                StreamName = "ArgOS_2_0_DHAL2",

                Parent = "ArgOS_2_0",

                Compliance = "Released",

            },

            new TreeModel

            {

                ChangeFlowsFromParent = true,

                ChangeFlowsToParent = true,

                StreamType = "Release",

                StreamName = "ArgOS_2_0_DHAL3",

                Parent = "ArgOS_2_0",

                Compliance = "Released",

            },

        };

        var output = MapToTreeModelJsonCollection(source);

        var json = JsonConvert.SerializeObject(output,Formatting.Indented);

        Console.WriteLine(json);

    }

    static ICollection<TreeModelJson> MapToTreeModelJsonCollection(ICollection<TreeModel> source)

    {

        // map all items

        var allItems = source.Select(e => new TreeModelJson

                                     {

                                         ChangeFlowsFromParent = e.ChangeFlowsFromParent.ToString().ToLower(),

                                         ChangeFlowsToParent = e.ChangeFlowsToParent.ToString().ToLower(),

                                         Compliance = e.Compliance,

                                         Parent = e.Parent ?? "none",

                                         StreamName = e.StreamName,

                                         StreamType = e.StreamType,

                                     }).ToList();

        // build tree structure

        foreach (var item in allItems)

        {

            var children = allItems.Where(e => e.Parent == item.StreamName).ToList();

            if (children.Any())

            {

                item.Children = children;

            }

        }

        // return only root items

        return allItems.Where(e => e.Parent == "none").ToList();

    }

​

    class TreeModel

    {

        public string StreamName { get; set; }

        public string ParentName { get; set; }

        public string StreamType { get; set; }

        public bool ChangeFlowsFromParent { get; set; }

        public bool ChangeFlowsToParent { get; set; }

        public string Compliance { get; set; }

        public string Parent { get; set; }

    }

​

    class TreeModelJson

    {

        [JsonProperty("ChangeFlowsFromParent")]

        public string ChangeFlowsFromParent { get; set; }

        [JsonProperty("ChangeFlowsToParent")]

        public string ChangeFlowsToParent { get; set; }

        [JsonProperty("StreamType")]

        public string StreamType { get; set; }

        [JsonProperty("streamName")]

        public string StreamName { get; set; }

        [JsonProperty("Parent")]

        public string Parent { get; set; }

        [JsonProperty("Compliance")]

        public string Compliance { get; set; }

        [JsonProperty("children", NullValueHandling = NullValueHandling.Ignore)]

        public ICollection<TreeModelJson> Children { get; set; }

    }

}