using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var c = (new CVBoxController()).GetCategories();

        c.Dump();

    }

    public class CVBoxController

{

    public List<CategoryNode> GetCategories()

    {

        var categories = new List<CategoriesList>

            {

                new CategoriesList { Id=1, Name="Cat 01", ParentId=0 },

                new CategoriesList { Id=2, Name="Cat 02", ParentId=0 },

                new CategoriesList { Id=3, Name="Cat 03", ParentId=0 },

                new CategoriesList { Id=4, Name="Cat 04", ParentId=0 },

                new CategoriesList { Id=5, Name="Cat 05", ParentId=0 },

                new CategoriesList { Id=6, Name="Cat 06", ParentId=1 },

                new CategoriesList { Id=7, Name="Cat 07", ParentId=6 },

                new CategoriesList { Id=8, Name="Cat 08", ParentId=3 },

                new CategoriesList { Id=9, Name="Cat 09", ParentId=4 },

                new CategoriesList { Id=10, Name="Cat 10", ParentId=9 },

                new CategoriesList { Id=11, Name="Cat 11", ParentId=10 }

            };

​

        return CreateCategoryTree(categories);

    }

​

    private List<CategoryNode> CreateCategoryTree(List<CategoriesList> categories)

    {

        List<CategoryNode> nodes = new List<CategoryNode>();

​

        foreach (var item in categories)

        {

            if (item.ParentId == 0)

                nodes.Add(new CategoryNode { Id = item.Id, Name = item.Name });

            else

            {

                CreateNode(nodes, item);

            }

        }

        return nodes;

    }

​

    private void CreateNode(List<CategoryNode> nodes, CategoriesList parent)

    {

        foreach (var node in nodes)

        {

            if (node.Id == parent.ParentId)

            {

                node.Children.Add(new CategoryNode { Id = parent.Id, Name = parent.Name });

            }

            else

            {

                CreateNode(node.Children, parent);

            }

        }

    }

}

​

public class CategoriesList

{

    public int Id { get; set; }

    public string Name { get; set; }

    public int ParentId { get; set; }

}

​

public class CategoryNode

{

    public int Id { get; set; }

    public string Name { get; set; }

    public List<CategoryNode> Children { get; set; }

​

    public CategoryNode()

    {

        Children = new List<CategoryNode>();

    }

}

}