public void Clear()
        {
            HttpContext httpContext = HttpContext.Current;

            if (HttpCallContext.IsHttpContextValid(httpContext))
            {
                httpContext.Items.Remove("MSExchangeLocalId");
                httpContext.Items.Remove("SingleContextIdKey");
            }
        }
 public bool CheckId()
 {
     return(HttpCallContext.IsHttpContextValid(HttpContext.Current));
 }