public async Task <IEnumerable <Entity> > GetAsync(
            int fromResultIndex,
            int toResultIndex,
            List <KeyValuePair <EntityFilterColumn, string> > filterColumn,
            EntitySortColumn sortColumn,
            Order order
            )
        {
            var
                url = BuildGetListRequestUrl(filterColumn, sortColumn, order);

            var
                rawJsonData = await HttpHelper.GetRawJsonDataAsync(url, fromResultIndex, toResultIndex);

            return(BuildGetListResponseObjects(rawJsonData));
        }
        private string BuildGetListRequestUrl(
            List <KeyValuePair <EntityFilterColumn, string> > filterColumn,
            EntitySortColumn sortColumn,
            Order order
            )
        {
            var
                url = string.Format("{0}?{1}sort({2}{3})",
                                    BaseUrl,
                                    filterColumn == null ? "" : string.Join("&", filterColumn.Select(_ => _.Key + "=" + _.Value)) + "&",
                                    order == Order.Asc ? "+" : "-",
                                    sortColumn.ToString()
                                    );

            return
                (url);
        }