private void lw_ItemAppearing(object sender, ItemVisibilityEventArgs e)
        {
            Dataset_F102 item = e.Item as Dataset_F102;

            currentItemIndex = GetF102_data_List.IndexOf(item);

            if (currentItemIndex > prevItemIndex)
            {
                scroll_UP = true;
            }
            else
            {
                scroll_UP = false;
            }

            if (currentItemIndex > 20 & scroll_UP == true)
            {
                cv_f102_dynamic.IsVisible = false;
            }

            else if (currentItemIndex == 0)
            {
                cv_f102_dynamic.IsVisible = true;
            }


            /*DisplayAlert("Check",
             *            Math.Round(Math.Pow(currentItemIndex, 1.8), 0).ToString() , "OK"
             *             );*/

            prevItemIndex = currentItemIndex;
        }
        public async void grid_item_tapped(object sender, ItemTappedEventArgs e)
        {
            Dataset_F102 selectedRow = e.Item as Dataset_F102;

            // if (selectedRow != null)

            // await App.MasterDetail.Detail.Navigation.PushAsync(new F101Page_byIndCode(tip, selectedRow.IndCode.ToString(), datesList.First().dt, selectedRow.regn));

            SearchBar1.IsVisible          = false;
            ListView_SearchBar1.IsVisible = false;
            Grid_f102_header.IsVisible    = true;
            lw.IsVisible = true;
            slice        = (string)ResDic["page_slice"];
            if (slice == "Part")
            {
                slice = "Section_by_Part" + selectedRow.Field_id.ToString();
            }
            else if (slice.Contains("Section_by_Part"))
            {
                slice = "Article_by_Section" + selectedRow.Field_id.ToString();
            }
            else if (slice.Contains("Article_by_Section"))
            {
                slice = "SymbCode_by_Article" + selectedRow.Field_id.ToString();
            }
            else if (slice.Contains("SymbCode_by_Article"))
            {
                slice = "Banks_by_symbol" + selectedRow.Field_id.ToString();
            }
            else if (slice.Contains("Banks_by_symbol"))
            {
                slice = "Exit_";
            }



            if (!slice.Contains("Exit_"))
            {
                await App.MasterDetail.Detail.Navigation.PushAsync(new F102Page(slice, -1, regn, dt_slice, filtered_bankname));
            }



            // DisplayAlert("Уведомление", selectedRow.Field_id.ToString(), "ОK");


            /*if (filtered_bankname != "0" & filtered_bankname != "БАНКОВСКАЯ СИСТЕМА РФ")
             * {
             *  //DisplayAlert("Уведомление", filtered_bankname, "ОK");
             *  GetF102_data_List_search_bar_filterd = GetF102_data_List.Where(x => x.regn == filtered_bankname).ToList();
             *  lw.ItemsSource = GetF102_data_List_search_bar_filterd;
             * }
             * else
             * {
             *  lw.ItemsSource = GetF102_data_List;
             * }*/

            /*Header_fieds_change(Label2_bankname, "Name_Part", filtered_bankname);
             * if (tip == 4) { chart(tip, indCode, (DateTime.Parse(dt_slice).AddMonths(-12)).ToString("yyyy-MM-dd"), dt_slice, filtered_bankname); }
             * else { chart(tip, indCode, (DateTime.Parse(dt_slice).AddMonths(-11)).ToString("yyyy-MM-dd"), dt_slice, filtered_bankname); }
             */
        }