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

public partial class _Default : System.Web.UI.Page 
{    
    protected void GridSource(object sender, GridNeedDataSourceEventArgs e)
    {
        List<MyObject> data = new List<MyObject>();
        for (int i = 0; i < 5; i++)
        {
            MyObject item = new MyObject { ID = i, Text = "Text " + i, Child = new NestedObject { Name ="Name " + i} };
            data.Add(item);
        }

        RadGrid1.DataSource = data;
    }
}

public class MyObject
{
    public int ID { get; set; }
    public string Text { get; set; }
    public NestedObject Child { get; set; }
}

public class NestedObject
{
    public string Name { get; set; }
}