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

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        RadTextBox rtb = new RadTextBox();
        rtb.ID = "RadTextBox1";
        Panel1.Controls.Add(rtb);
        Button btn = new Button();
        btn.ID = "Button1";
        btn.Text = "Click me";
        Panel1.Controls.Add(btn);
    }
}