oap_labs/WpfApp1/MainWindow.xaml.cs

using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using WpfApp1.model;

namespace WpfApp1
{

    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        private void Invalidate()
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs("ClientList"));
        }
        public string selectedCategory = "Все категории";
        public ClientPrice? selectedPrice = null;

        private IEnumerable<Client> _ClientList;
        public IEnumerable<Client> ClientList
        {
            get
            {
                var res = _ClientList;
                res = res
                   .Where(c => (selectedPrice == null || (c.Price >= selectedPrice.PriceFrom && c.Price < selectedPrice.PriceTo)))
                   .Where(c => (c.Category == selectedCategory || selectedCategory == "Все категории"));


                if (searchFilter != "")
                    res = res.Where(c => c.Name.IndexOf(
                        searchFilter,
                        StringComparison.OrdinalIgnoreCase) >= 0 || c.Category.IndexOf(
                        searchFilter,
                        StringComparison.OrdinalIgnoreCase) >= 0 || c.Place.IndexOf(
                        searchFilter,
                        StringComparison.OrdinalIgnoreCase) >= 0);
                if (sortAsc) res = res.OrderBy(c => c.Price);
                else res = res.OrderByDescending(c => c.Price);
                if (sortAsc) res = res.OrderBy(c => c.Price);
                else res = res.OrderByDescending(c => c.Price);

                return res;
            }
            set
            {
                _ClientList = value;
            }
        }
        public List<Client> Client { get; set; }
        public List<ClientCategory> ClientCategoryList { get; set; }
        public List<ClientPrice> ClientPriceList { get; set; }


        public MainWindow()
        {
            {
                InitializeComponent();
                DataContext = this;
                Globals.dataProvider = new LocalDataProvider();
                ClientList = Globals.dataProvider.getClient();
                ClientPriceList = Globals.dataProvider.getPrice().ToList();
                ClientCategoryList = Globals.dataProvider.getCategory().ToList();
                ClientCategoryList.Insert(0, new ClientCategory() { title = "Все категории" });
            }
        }

        private void ExitButton_Click(object sender, RoutedEventArgs e)
        {
            Application.Current.Shutdown();

        }
        private string searchFilter = "";

        private void SearchFilter_KeyUp(object sender, KeyEventArgs e)
        {
            searchFilter = SearchFilterTextBox.Text;
            Invalidate();
        }

        private void ClientCategoryFilterComboBox_selectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
        {
            selectedCategory = (CategoryFilterComboBox.SelectedItem as ClientCategory).title;
            Invalidate();
        }
        private void ClientPriceFilterComboBox_selectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
        {
            selectedPrice = PriceFilterComboBox.SelectedItem as ClientPrice;
            Invalidate();
        }

        private bool sortAsc = true;

        private void RadioButton_Checked(object sender, RoutedEventArgs e)
        {
            sortAsc = (sender as RadioButton).Tag.ToString() == "1";
            Invalidate();
        }

        private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {

        }
    }
    interface IDataProvider
    {
        IEnumerable<Client> getClient();
        IEnumerable<ClientPrice> getPrice();
        IEnumerable<ClientCategory> getCategory();
    }
    public class LocalDataProvider : IDataProvider
    {
  
        public IEnumerable<ClientCategory> getCategory()
        {
            return new ClientCategory[]
            {
                new ClientCategory()
                {
                    title="По России"

                },
                new ClientCategory()
                {
                    title="За границей"
                },
            };
        }
        public IEnumerable<ClientPrice> getPrice()
        {
            return new ClientPrice[]
            {
                    new ClientPrice()
                    {
                        title = "Все цены",
                        PriceFrom = 500,
                        PriceTo = 30000
                    },
                    new ClientPrice()
                    {
                        title = "Низкая цена",
                        PriceFrom = 500,
                        PriceTo = 3000

                    },
                    new ClientPrice()
                    {
                        title = "Средняя цена",
                        PriceFrom = 3000,
                        PriceTo = 15000

                    },
                    new ClientPrice()
                    {
                        title = "Высокая цена",
                        PriceFrom = 15000,
                        PriceTo = 30000

                    }


            };
        }

        public IEnumerable<Client> getClient()
        {
            return new Client[]{
            new Client{
                Name = "Никита",
                Age = 20,
                Price=2300,
                Category="По России",
               Place="Москва"},
            new Client{
                Name = "Маша",
                Age = 15,
                Price=5000,
                Category="По России",
                Place="Сочи"},
            new Client{
                Name = "Алиса",
                Age = 35,
                Price=15000,
                Category="За границей",
                Place="Токио"},
             new Client{
                 Name = "Леша",
                Age = 19,
                Price=20000,
                Category="За границей",
                Place="Южная Корея"},
             new Client{
                 Name = "Андрей",
                Age = 28,
                Price=3000,
                Category="По России",
                Place="Крым"},
                 new Client{
                 Name = "Костя",
                Age = 14,
                Price=18000,
                Category="За границей",
               Place="Токио"},
             new Client{
                 Name = "Даша",
                Age = 12,
                Price=25000,
                Category="За границей",
                Place="Лондон"},
             new Client{
                 Name = "Ольга",
                Age = 55,
                Price=22000,
                Category="За границей",
               Place="Люксембург"},
             new Client{
                  Name = "Катя",
                Age = 30,
                Price=1500,
                Category="По России",
               Place="Адлер"},
             new Client{
                 Name = "Анжела",
                Age = 61,
                Price=25000,
                Category="За границей",
                Place="Мальдивы"},
             new Client{
                  Name = "Миша",
                Age = 17,
                Price=30000,
                Category="За границей",
                Place="Дубаи"},
 
        };

        }
    }
}