AvaloniaKnuScool/ViewModels/CoursesListViewModel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using AvaloniaApplication1.Models;
using Microsoft.EntityFrameworkCore;
using ReactiveUI;

namespace AvaloniaApplication1.ViewModels
{
	public class CoursesListViewModel : ReactiveObject
	{
		public static ScoolContext DB = new ScoolContext();
        private List<Course>? courses;
        public List<Course>? Courses { get => courses; set => this.RaiseAndSetIfChanged(ref courses, value); }

        public CoursesListViewModel()
		{
            Courses = DB.Courses.Include(x=>x.TeachersCourses).ToList();
        }

   

		public static List<string> OrderNameOrHours => new List<string>() {"Áåç ñîðòèðîâêè", "Ïî èìåíè À-ß", "Ïî èìåíè ß-À", "Ïî êîëè÷åñòâó ÷àñîâ (ïî âîçðàñòàíèþ)", "Ïî êîëè÷åñòâó ÷àñîâ (ïî óáûâàíèþ)" };

		private string selectedNameOrHour = OrderNameOrHours[0];

		public string SelectedNameOrHour
		{
            get => selectedNameOrHour;
            set
            {
                selectedNameOrHour = value;
                Filter();
            }
        }

        public static List<string> FilterByHours => new List<string>() { "Áåç ôèëüòðà", "50 ÷àñîâ èëè ìåíüøå", "îò 50 äî 100 ÷àñîâ", "áîëåå 100 ÷àñîâ" };

        private string selectedFilter = FilterByHours[0];

        public string SelectedFilter
        {
            get => selectedFilter;
            set
            {
                selectedFilter = value;
                Filter();
            }
        }

        private string nameOrHoursFind;

        public string NameOrHoursFind
        {
            get => nameOrHoursFind;
            set
            {
                nameOrHoursFind = value;
                Filter();
            }
        }

        public void Filter()
		{
            Courses = DB.Courses.Include(x => x.TeachersCourses).ToList();

            if(SelectedNameOrHour != "Áåç ñîðòèðîâêè")
            {
                switch(SelectedNameOrHour)
                {
                    case "Ïî èìåíè À-ß":
                        Courses = Courses.OrderBy(x=>x.Course1).ToList();
                        break;
                    case "Ïî èìåíè ß-À":
                        Courses = Courses.OrderByDescending(x => x.Course1).ToList();
                        break;
                    case "Ïî êîëè÷åñòâó ÷àñîâ (ïî âîçðàñòàíèþ)":
                        Courses = Courses.OrderBy(x => x.HoursCount).ToList();
                        break;
                    case "Ïî êîëè÷åñòâó ÷àñîâ (ïî óáûâàíèþ)":
                        Courses = Courses.OrderByDescending(x => x.HoursCount).ToList();
                        break;
                }
            }

            if (SelectedFilter != "Áåç ôèëüòðà")
            {
                switch (SelectedNameOrHour)
                {
                    case "50 ÷àñîâ èëè ìåíüøå":
                        Courses = Courses.Where(x => x.HoursCount <= 50).ToList();
                        break;
                    case "îò 50 äî 100 ÷àñîâ":
                        Courses = Courses.Where(x => x.HoursCount > 50 && x.HoursCount <= 100).ToList();
                        break;
                    case "áîëåå 100 ÷àñîâ":
                        Courses = Courses.Where(x => x.HoursCount > 100).ToList();
                        break;
                }
            }

            if(NameOrHoursFind != null && NameOrHoursFind != "")
            {
                Courses = Courses.Where(x=>x.Course1.ToLower().Contains(NameOrHoursFind.ToLower()) || NameOrHoursFind == Convert.ToString(x.HoursCount)).ToList();
            }
        }
	}
}