protected override void OnException(
        ExceptionContext filterContext
        )
    {
        try
        {
            Error error = ControllerCommon.ProcessException(filterContext);

            // return error
            filterContext.Result = HandleError(error.Type);
            filterContext.ExceptionHandled = true;
        }
        catch (Exception ex)
        {
            Logger.Instance.LogImportantInformation(ex.Message, 0, Constants.EventSourcePortal);
        }
    }

    #endregion

    #region Private Methods and Members

    private ActionResult HandleError()
    {
        return HandleError(Error.ErrorType.Unknown);
    }

    private ActionResult HandleError(
        Error.ErrorType errorType
        )
    {
        // set return status code
        HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;

        Logger.Instance.LogImportantInformation(((int)errorType).ToString(CultureInfo.InvariantCulture), 0, Constants.EventSourcePortal);

        // return error type
        return Content(((int)errorType).ToString(CultureInfo.InvariantCulture), "text/plain");
    }