/// <summary>
 /// Aktualizuje hodnotu
 /// </summary>
 /// <param name="key">Guid ktory chceme aktualizovat</param>
 /// <param name="date">Datum ktory chceme ulozit</param>
 public static void UpdateValue(Guid key, DateTimeOffset date)
 {
     if (String.IsNullOrWhiteSpace(WebApplication.AccessTokenKey))
     {
         return;
     }
     String value = key.ToString().Replace("-", "");
     HttpContext current = HttpContext.Current;
     if (current != null)
     {
         HttpRequest request = current.Request;
         if (request != null)
         {
             HttpCookie cookie = request.Cookies.Get(value);
             if (cookie == null)
             {
                 cookie = new HttpCookie(value);
             }
             value = Utility.EncodeValue(WebApplication.AccessTokenKey, date.ToIso8601String());
             cookie.Value = value;
             current.Response.SetCookie(cookie);
         }
     }
 }