public class ListDepartments

    {

        public int id { get; set; }

        public int? parent_id { get; set; }

        public string short_name { get; set; }

        public string name { get; set; }

        public DateTime date_set { get; set; }

        public DateTime date_end { get; set; }

    }

    public class TreeDepartments

    {

        public int? id { get; set; }

        public IEnumerable<ListDepartments> children { get; set; }

    }

@model EconomistMVC.Models.TreeDepartments

@if (Model.children.Where(x => x.parent_id == Model.id).Any())

    {

        <ul>

            @foreach (var node in Model.children)

            {

                if (node.parent_id == Model.id)

                {

                    <a>@node.short_name</a>

                    EconomistMVC.Models.TreeDepartments inner = new EconomistMVC.Models.TreeDepartments

                    {

                        id = node.id,

                        children = Model.children

                    };

                    @Html.Partial("TreeDepartments", inner)

                }

            }

        </ul>

    }

   public static TabelContext TabelContext = new TabelContext();

        public List<Department> Dep = TabelContext.GetDepartments().ToArray().ToList();

        // GET: TreeDepartments

        public ActionResult TreeDepartments()

        {

              TreeDepartments model = new TreeDepartments()

            {

                children = Dep.Select(x => new ListDepartments(x)) 

            };

            return View(model);

         }

 children = Dep.Select(x => new ListDepartments { id=x.DepId})