using System;

using System.Collections.Generic;

using System.Linq;

using System.Xml;

using System.Data;

public class Program

{

    public static void Main()

    {

        DataTable dt = new DataTable("table");

            dt.Columns.Add("ParentId", typeof(int));

            dt.Columns.Add("ParentName", typeof(string));

            dt.Columns.Add("ChildId", typeof(string));

            dt.Columns.Add("ChildName", typeof(string));

​

            DataRow row1 = dt.NewRow();

            row1["ParentId"] = 1;

            row1["ParentName"] = "John";

            row1["ChildId"] = "4";

            row1["ChildName"] = "Suzy";

            dt.Rows.Add(row1);

​

            DataRow row2 = dt.NewRow();

            row2["ParentId"] = 1;

            row2["ParentName"] = "John";

            row2["ChildId"] = "5";

            row2["ChildName"] = "James";

            dt.Rows.Add(row2);

​

            DataRow row3 = dt.NewRow();

            row3["ParentId"] = 2;

            row3["ParentName"] = "Sally";

            row3["ChildId"] = "4";

            row3["ChildName"] = "Suzy";

            dt.Rows.Add(row3);

​

            DataRow row4 = dt.NewRow();

            row4["ParentId"] = 2;

            row4["ParentName"] = "Sally";

            row4["ChildId"] = "5";

            row4["ChildName"] = "James";

            dt.Rows.Add(row4);

​

            var query = dt.AsEnumerable().GroupBy(x => x.Field<string>("ParentName"))

                                         .Select(x => new Parent

                                         {

                                             Name = x.Key,

                                             Child = x.Select(z => new Children

                                             {

                                                 ChildID = z.Field<string>("ChildId"),

                                                 Name = z.Field<string>("ChildName")

                                             }).ToList()

                                         });

​

            foreach (var item in query)

            {

                Console.WriteLine("ParentName : {0}", item.Name);

                foreach (var child in item.Child)

                {

                    Console.WriteLine("\tChildId: {0}", child.ChildID);

                    Console.WriteLine("\tChildName: {0}", child.Name);

                    Console.WriteLine();

                }

                Console.WriteLine("-----------------------------------");

            }

        }

    }

}

​

 public class Parent

    {

        public int ParentID = 0;

        public string Name = string.Empty;

        public List<Children> Child = new List<Children>();

    }

​

    public class Children

    {

        public string ChildID = "0";

        public string Name = string.Empty;

    }