ViewState in Dynamic Control

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

public partial class UserControl_ContactDetails : System.Web.UI.UserControl
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //Retain the state of controls
        txtAddress1.Text = Request.Form[txtAddress1.UniqueID];
        txtAddress2.Text = Request.Form[txtAddress2.UniqueID];
        txtCity.Text = Request.Form[txtCity.UniqueID];
        txtFirstName.Text = Request.Form[txtFirstName.UniqueID];
        txtLastName.Text = Request.Form[txtLastName.UniqueID];
        txtZip.Text = Request.Form[txtZip.UniqueID];
    }
}