demo/Demo/MainWindow.axaml.cs

using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Media;
using Avalonia.Media.Imaging;
using Avalonia.Platform;
using Avalonia.Platform.Storage;
using Demo.EntityModels;
using Demo.Utils;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using Tmds.DBus.Protocol;

namespace Demo
{
    public partial class MainWindow : Window
    {
        //flags
        private bool AdminMode = false;
        private bool IsFiltred = false;
        //null - nothing, 0 - asc, 1 - desc
        private bool? SortedMode = null;


        //changedList
        private string SearchWord  = "";


        //constants for comboboxes
        private string[] sortValues = new string[3] { "îòñóò", "ïî âîçðàñò.", "ïî óáûâ." }; 

        private List<Service> services = new List<Service>()
            {
                new Service(){ ServiceName = "Abc", ServiceDiscount="Abc", ServicePriceMinutes = "Abc" },
                new Service(){ ServiceName = "cba", ServiceDiscount="cba", ServicePriceMinutes = "cba" },
                new Service(){ ServiceName = "bca", ServiceDiscount="bca", ServicePriceMinutes = "bca" },
                new Service(){ ServiceName = "ccb", ServiceDiscount="ccb", ServicePriceMinutes = "ccb" }
            };
      
        public MainWindow()
        {

            InitializeComponent();


            MyImage.Source = new Bitmap(AssetLoader.Open(new System.Uri("avares://Assets/service_layout.png")));

            services = Context
                .DbContext
                .Services.Select(service => new Service
                {
                    ServiceDiscount = service.Discount.ToString(),
                    ServiceName = service.Title,
                    ServicePriceMinutes = $"{service.Cost}/{service.Durationinminutes}"
                }).ToList();

            SortComboBox.ItemsSource = sortValues;
            SortComboBox.SelectedIndex = 0;
            DisplayService();
        }

        private void Button_Click(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
        {
            AdminPanel.IsVisible = !AdminPanel.IsVisible;
        }

        private void SearchTextBox_TextChanging(object? sender, Avalonia.Controls.TextChangingEventArgs e)
        {
            string inputValue = (sender as TextBox).Text;
            SearchWord = inputValue.ToLower();
            DisplayService();
        }

        public async void ChangeModeButton_ClickAsync(object sender, RoutedEventArgs e)
        {
            var changeModeDialog = new ChangeModeDialog();
            AdminMode = await changeModeDialog.ShowDialog<bool>(this);
            AdminPanel.IsVisible = AdminMode;
            DisplayService();
        }

        private void DisplayService()
        {
            List<Service> displayList = services;
            if (!string.IsNullOrEmpty(SearchWord)) {
                displayList = 
                    displayList
                    .Where(x => 
                    x.ServiceName
                    .ToLower()
                    .Contains(SearchWord)
                    ).ToList();
            }

            switch (SortedMode)
            {
                case true: displayList =
                        displayList
                        .OrderBy(
                            service => 
                            service.ServiceName)
                        .ToList(); break;
                case false: displayList = 
                        displayList
                        .OrderByDescending(
                            service => 
                            service.ServiceName)
                        .ToList(); break;
                case null:
                    break;

            }

  
            ServiceList.ItemsSource = displayList
                .Select(service => service.SetAdminMode(AdminMode))
                .ToList();

            CountValues.Text = $"Îòîáðæàåòñÿ:{displayList.Count}/Âñåãî:{services.Count}";
        }



        class Service()
        {

            public string ServiceName { get; set; }
            public string ServicePriceMinutes { get; set; }
            public string ServiceDiscount { get; set; }
            public bool AdminMode { get; set; } = false;

            public Service SetAdminMode(bool mode)
            {
                this.AdminMode = mode;
                return this;
            }

        }

        private void SortComboBox_SelectionChanged(object? sender, Avalonia.Controls.SelectionChangedEventArgs e)
        {
            int selectedIndex = (sender as ComboBox).SelectedIndex;
            switch (selectedIndex) {
                case 1: SortedMode = false; break;
                case 2: SortedMode = true; break;
                default:
                    SortedMode = null; break;
            }
            DisplayService();
        }

       
    }
}