Agents/MainWindow.axaml.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Media.Imaging;
using Avalonia.Platform;
using System.Reflection;
using System;
using Agents.Models;
using System.Collections.ObjectModel;
using Avalonia.Interactivity;
using System.Linq;
using System.Runtime.ExceptionServices;
using System.Collections.Immutable;

namespace Agents
{
    public partial class MainWindow : Window
    {
        static User11Context db = new User11Context();
        ObservableCollection<Agent> AgentsitemSource = new ObservableCollection<Agent>(db.Agents.OrderBy(it=>it.Title));
        ObservableCollection<Agent> ListAgents2;
        public MainWindow()
        {
            InitializeComponent();
            ListAgents.ItemsSource = AgentsitemSource;
            ListAgents2 = AgentsitemSource;
        }
        private void ListBox_SelectionChanged(object? sender, Avalonia.Controls.SelectionChangedEventArgs e)
        {
            if(sender != null)
            {
                try
                {
                    UpdateInfo();
                }
                catch (Exception ex)
                {
                    ExceptionDispatchInfo.Capture(ex).Throw();
                }
            }
        }
        private void SortAg(object? sender, Avalonia.Controls.SelectionChangedEventArgs e)
        {
            if (sender != null)
            {
                try
                {
                    SortAgent();
                }
                catch (Exception ex)
                {
                    ExceptionDispatchInfo.Capture(ex).Throw();
                }
            }
        }

        void SortAgent()
        {
            switch (SortListAgents.SelectedIndex)
            {
                case 1: AgentsitemSource = new ObservableCollection<Agent>(AgentsitemSource.OrderByDescending(it => it.Title).ToList()); break;
                case 2: AgentsitemSource = new ObservableCollection<Agent>(AgentsitemSource.OrderBy(it => it.Title).ToList()); break;
                default: AgentsitemSource = ListAgents2; break;
            }

            ListAgents.ItemsSource = new ObservableCollection<Agent>(AgentsitemSource);
        }

        private void ComboBox_SelectionChanged_3(object? sender, Avalonia.Controls.SelectionChangedEventArgs e)
        {
            if (sender != null)
            {
                try
                {
                    UpdateInfo();
                }
                catch (Exception ex)
                {
                    ExceptionDispatchInfo.Capture(ex).Throw();
                }
            }
        }

        private void ButtonUpdate(object sender, RoutedEventArgs e)
        {
            UpdateInfo();
        }

        private void UpdateInfo()
        {
            Agent? agent = db.Agents.Where(it => it == ListAgents.SelectedItem).FirstOrDefault();
            if (agent != null)
            {
                Productsale? PS = db.Productsales.Where(it => it.Agentid == agent.Id).FirstOrDefault();
                var prods = db.Productsales
                .Where(PWS => PWS.Agentid == agent.Id)
                .Select(PWS => new Product
                {
                    Title = PWS.Product.Title,
                    Image = PWS.Product.Image,
                    Producttypeid = PWS.Product.Producttypeid,
                    Productionpersoncount = PWS.Product.Productionpersoncount,
                    Productionworkshopnumber = PWS.Product.Productionworkshopnumber,
                    Mincostforagent = PWS.Product.Mincostforagent,
                    Description = PWS.Product.Description,
                    Articlenumber = PWS.Product.Articlenumber
                }).ToList();

                switch (SortListProductAgents.SelectedIndex)
                {
                    case 1: prods = prods.OrderBy(p => p.Title).ToList(); break;
                    case 2: prods = prods.OrderByDescending(p => p.Title).ToList(); break;
                    default: break;
                }

                ListProducts.ItemsSource = new ObservableCollection<Product>(prods);
            }
        }
        private void ButtonAgentEidtor(object sender, RoutedEventArgs e)
        {
            new AgentEidtor().Show();
            Close();
        }

        private void ButtonProductEidtor(object sender, RoutedEventArgs e)
        {
            new ProductEditor().Show();
            Close();
        }

        private void ButtonAddProduct(object sender, RoutedEventArgs e)
        {
            new AddProduct().Show();
            Close();
        }

        void Button_search(object sender, RoutedEventArgs e)
        {
            string? Search = search.Text;
            if (search.Text != "")
            {
                AgentsitemSource = new ObservableCollection<Agent>(db.Agents.Where(it => it.Title == Search || 
                                                                                         it.Address == Search || 
                                                                                         it.Inn == Search || 
                                                                                         it.Kpp == Search || 
                                                                                         it.Directorname == Search || 
                                                                                         it.Phone == Search || 
                                                                                         it.Email == Search || 
                                                                                         it.Priority == int.Parse(Search)
                                                                                         ));
                if (AgentsitemSource != null)
                {
                    ListAgents.ItemsSource = AgentsitemSource;
                    ListAgents2 = AgentsitemSource;
                    SortAgent();
                }
                else
                {
                    ListAgents.ItemsSource = null;
                }
            }
            else
            {
                AgentsitemSource = new ObservableCollection<Agent>(db.Agents.OrderBy(it => it.Title));
                ListAgents.ItemsSource = AgentsitemSource;
                ListAgents2 = AgentsitemSource;
                SortAgent();
            }
        }
    }
}