show textbox on selecting radio button

Hello My dear Friend use this, it will be helpful.

Design Page aspx
================

<asp:RadioButton ID="RadioButton1" runat="server" AutoPostBack="true"
            oncheckedchanged="RadioButton1_CheckedChanged"/>

        <asp:TextBox ID="TextBox1" runat="server" Visible="false" ></asp:TextBox>

Code Page cs
============

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class RadioButton_Textbox : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void RadioButton1_CheckedChanged(object sender, EventArgs e)
    {

        if(RadioButton1.Checked)
        {
            TextBox1.Visible = true;
        }
        else
        {
            TextBox1.Visible = false;

        }
    }
}

BYE.............