How to copy data from one datatable to another datatable in c# without copy function

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

namespace adi
{
    public partial class WebForm4 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            copy_data();
        }
        public void copy_data()
        {
            DataTable dt1 = new DataTable();
            dt1.Columns.AddRange(new DataColumn[1] { new DataColumn("Id") });
            dt1.Rows.Add("4");
            dt1.Rows.Add("5");
            dt1.Rows.Add("6");
            dt1.Rows.Add("7");
            dt1.Rows.Add("8");
            dt1.Rows.Add("11");
            dt1.Rows.Add("13");
            DataTable dt2 = new DataTable();
            dt2.Columns.AddRange(new DataColumn[1] { new DataColumn("Id") });
            for (int i = 0; i < dt1.Rows.Count; i++)
            {
                for (int j = 0; j < dt1.Columns.Count; j++)
                {
                    dt2.Rows.Add(dt1.Rows[i][j]);
                }
            }

        }
    }
}