Following is example for adding a cooking and fetching value from an existing cookie
Creating a new cookie
HttpCookie Testcookie = new HttpCookie("CookieName");
Testcookie.Value = "CookieValue";
Testcookie.Expires = DateTime.Now.AddMinutes(5);
Response.Cookies.Add(Testcookie);
Retrive value of an existing cookie
HttpCookie TestCookie = Request.Cookies["CookieName"];
if (TestCookie!=null)
{
Response.Write("Cookie values is "+TestCookie.Value.ToString());
}
Hope this will be helpful.