MVVM With SingeleTonSean

Disclaimer

I'm learning MVVM pattern and i started this repo as exercising while coding along with SingeleToneSean's Playlist about MVVM I donw own the idea of the apps i summerise the key features here to help myself learn more and my use this reop as example of abstract ideas and design patterns examples reasource.

Preview of the app

Purpose

The app should simply allow a costumer to reserve a room in fictional hotel inserting 5 inputs

1. UserName
2. FloorNum
3. RoomNum
4. Date of start
5. Date of end

It should show list of all the reservation validate new ones and update SQL local Server .

Validation

All this properties are binded to the MakeReservationViewModel properties :

MVVM-Hotel-Reservation-WPF/View/Views/MakeReservationView.xaml

Lines 52 to 55 in 3efa25d

	<TextBlock Grid.Row="0" Text="Room Number"/>
	<TextBox Grid.Row="1" Text="{Binding RoomID ,UpdateSourceTrigger=PropertyChanged}" />
	<TextBlock Grid.Column="1" Grid.Row="0" Text="Floor Number"/>
	<TextBox Grid.Column="1" Grid.Row="1" Text="{Binding FloorNum ,UpdateSourceTrigger=PropertyChanged}" />

Using Commands I enable and disable the button of submiting checking if there is username , room number and floor number if so calls the OnCanExecute() that invokes the boolian method :

MVVM-Hotel-Reservation-WPF/ViewModel/Commands/MakeReservationCommand.cs

Lines 66 to 72 in 3efa25d

	public override bool CanExecute(object? parameter)
	{
	return !string.IsNullOrEmpty(_makeReservationViewModel.UserName)&&
	_makeReservationViewModel .FloorNum>0
	&& _makeReservationViewModel.RoomID>0
	&& base.CanExecute(parameter);
	}

When CanExecute is true the submit button beacome enabled and clicking it calls async method that uses a validator objects to check if there is error in the data / conflict with reservation from the data base
The validator named DatabaseReservationConflictValidator and implementing IReservationConflicValidator so the app is open for new Validetors addition in the future

MVVM-Hotel-Reservation-WPF/Model/Services/ReservationConflictValidator/DatabaseReservationConflictValidator.cs

Lines 19 to 32 in 3efa25d

	public async Task<Reservation> GetConflictReservation(Reservation reservation)
	{
	using (ReserveRoomDBContext context = _dbContextFactory.CreateDbContext())
	{
	ReservationDTO reservationDTO = await context.Reservations.
	Where(r => r.FloorNum== reservation.roomID.FloorNum).
	Where(r => r.RoomNum== reservation.roomID.RoomNum).
	Where(r => r.End>reservation.Start ).
	Where(r=> r.Start < reservation.End).
	FirstOrDefaultAsync();
	if (reservationDTO is null)
	return null;
	return ToReservationMapper(reservationDTO);
	}