Get Anonymous Object using C#

Question

 

class Program
    {
        static void Main(string[] args)
        {
            List<AssignedUsers> assUser = new List<AssignedUsers>() {
            new AssignedUsers(){Id=1,name="Lao Lao",parent=0},
             new AssignedUsers(){Id=2,name="Bo Miao",parent=1},
              new AssignedUsers(){Id=3,name="Li Xin",parent=2},
               new AssignedUsers(){Id=4,name="Su Miao",parent=1},
                new AssignedUsers(){Id=5,name="Pang Pang",parent=6},
                 new AssignedUsers(){Id=6,name="Dan Dan",parent=6},
                  new AssignedUsers(){Id=7,name="Hong Miao",parent=1}
        };
        }
        public class AssignedUsers
        {
            public int Id { get; set; }
            public string name { get; set; }
            public int parent { get; set; }
            public string titlenew { get; set; }
        }
    }

 

 How to get below object : 

{
  "id": "1",
  "name": "Lao Lao",
  "titlenew": "general manager",
  "children": [
    {
      "id": "2",
      "name": "Bo Miao",
      "titlenew": "department manager",
      "parentId": "1",
      "children": [
        {
          "id": "3",
          "name": "Li Xin",
          "titlenew": "senior engineer",
          "parentId": "2"
        }
      ]
    },
    {
      "id": "4",
      "name": "Su Miao",
      "titlenew": "department manager",
      "children": [
        {
          "id": "5",
          "name": "Tie Hua",
          "titlenew": "senior engineer",
          "parentId": "4"
        },
        {
          "id": "6",
          "name": "Hei Hei",
          "titlenew": "senior engineer",
          "children": [
            {
              "id": "7",
              "name": "Pang Pang",
              "titlenew": "engineer",
              "parentId": "6"
            },
            {
              "id": "8",
              "name": "Dan Dan",
              "titlenew": "UE engineer",
              "parentId": "6"
            }
          ],
          "parentId": "4"
        }
      ],
      "parentId": "1"
    },
    {
      "id": "9",
      "name": "Hong Miao",
      "parentId": "1"
    }
  ]
}