private async Task getItemsAsync()
        {
            string arTerm = ARTermsOptions.SelectedValue != null?ARTermsOptions.SelectedValue.ToString() : "1";

            string itemType = ItemTypeList.SelectedValue != null?ItemTypeList.SelectedValue.ToString() : null;

            string trademarkKey = TrademarkList.SelectedValue != null?TrademarkList.SelectedValue.ToString() : null;

            string countTry  = ItemQuatity.Text;
            string itemKey   = ItemKey.Text;
            bool   extraInfo = ExtraInfo.IsChecked ?? false;

            int qty = 0;

            if (String.IsNullOrEmpty(countTry) || !int.TryParse(countTry, out qty))
            {
                qty = 0;
            }

            DateTime start = DateTime.Now;
            DateTime end;

            try
            {
                string msg;

                if (!String.IsNullOrEmpty(itemKey)) //single item fetch
                {
                    var result = await client.GetItemDetails(itemKey, itemKey, arTerm, 0, extraInfo);

                    msg = result;
                }
                else //fetch multiple items
                {
                    if (!String.IsNullOrEmpty(itemType) || !String.IsNullOrEmpty(trademarkKey))
                    {
                        var result = await client.GetItemsFilteredAsync(itemType, trademarkKey, "itemFiltered", arTerm, qty, extraInfo);

                        msg = result;
                    }
                    else
                    {
                        var result = await client.GetAllItemsAsync("allItems", qty, arTerm, extraInfo);

                        msg = result;
                    }
                }

                end = DateTime.Now;
                MessageBox.Show(String.Format("Vrijeme izvođenja: {2} minuta i {1} sekundi, {0}", msg, (end - start).Seconds, (end - start).Minutes));
            }
            catch (Exception ex)
            {
                ExceptionHandler.Log(ex, ctx.Directory);
                end = DateTime.Now;
                MessageBox.Show(String.Format("Došlo je do greške. Vrijeme izvođenja: {0}", (end - start).TotalSeconds));
            }
        }