.NET表单,保留跨会话的文本字段？

Session["myText"] = textBox1.Text;

if (Session["myText"] != null)
{
    textBox1.Text = Session["myText"].ToString();
}

ViewState["myText"] = textBox1.Text;

if (ViewState["myText"] != null)
{
    textBox1.Text = ViewState["myText"].ToString();
}

HttpCookie cookie = new HttpCookie("myText");
cookie.Value = textBox1.Text;
cookie.Expires = DateTime.Now.AddDays(1);
Response.Cookies.Add(cookie);

if (Request.Cookies["myText"] != null)
{
    textBox1.Text = Request.Cookies["myText"].Value;
}