Exam_Tour_Ageev/Ageev_Exam_Tour/ViewModel/HotelList.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace Ageev_Exam_Tour.Model
{
    internal class HotelList : INotifyPropertyChanged
    {

        public event PropertyChangedEventHandler PropertyChanged;
        

        // Take All Lines from DB
        List<Hotel> hotelList;
        public List<Hotel> ListOfHotel
        {
            get => hotelList;
            set
            {
                hotelList = value;
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(nameof(ListOfHotel)));        
            }
        }


        // Take the only part
        List<Hotel> chosenHotels;
        public List<Hotel> ChoosenHotels 
        { 
            get => chosenHotels; 
        
            set
            {
                chosenHotels = value;
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(nameof(ChoosenHotels)));
            } 
        }

        // The current page
        private int _currentPage;
        public int CurrentPage { 
            get => _currentPage; 
            set{
                _currentPage = value;
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(nameof(CurrentPage)));
                NavigationOfHotels();
            }
        }             
        
        // All pages
        private int _numberOfPage;
        public int NumberOfPage
        { 
            get => _numberOfPage; 
            set{
                _numberOfPage = value;
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(nameof(NumberOfPage)));
            }
        }

        // Index of array of pageItems
        private int _selectedRecord;
        public int SelectedRecord { 
            get => _selectedRecord; 
            set
            {
                _selectedRecord = value;
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(nameof(SelectedRecord)));

                ChangeElementsAndPages();

                if (CurrentPage > NumberOfPage)
                    CurrentPage = NumberOfPage;
                
                NavigationOfHotels();

            }
        }


        // Our pages there 
        private int[] pageItems;
        public int[] PagetItems  { get => pageItems; }

        public HotelList()
        {
            hotelList = GeneralData.myDataBase.Hotel.ToList();


            pageItems = new int[] { 10, 15, 20, 25 };

            // set as default 10 elements from DB
            _selectedRecord = 0;
            chosenHotels = hotelList.Take(pageItems[SelectedRecord] ).ToList();


            // Sets the page where we are
            _currentPage = 1;

            // Sets the default of Items
            _numberOfPage = (int)Math.Ceiling((decimal) hotelList.Count() / (decimal)pageItems[NumberOfPage]);

        }

        public void ChangeElementsAndPages()
        {
            // Update the choosen element
            ChoosenHotels = ListOfHotel.Take(pageItems[SelectedRecord]).ToList();

            // Update the number of page
            NumberOfPage = (int)Math.Ceiling((decimal)ListOfHotel.Count() / (decimal)pageItems[SelectedRecord]);
        }


        private void NavigationOfHotels()
        {
            ChoosenHotels = ListOfHotel.
                Skip( (CurrentPage-1) * pageItems[SelectedRecord]).Take(pageItems[SelectedRecord]).ToList();
        }

    }
}