Untitled

using System;
using System.ComponentModel;
using System.Windows;

namespace WpfApp
{
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        private DateTime? _selectedDate;
        private string _selectedTime;

        public DateTime? SelectedDate
        {
            get => _selectedDate;
            set
            {
                _selectedDate = value;
                OnPropertyChanged(nameof(SelectedDate));
                OnPropertyChanged(nameof(DisplayDateTime)); // Notify UI of changes
            }
        }

        public string SelectedTime
        {
            get => _selectedTime;
            set
            {
                _selectedTime = value;
                OnPropertyChanged(nameof(SelectedTime));
                OnPropertyChanged(nameof(DisplayDateTime)); // Notify UI of changes
            }
        }

        public string DisplayDateTime => 
            $"{SelectedDate?.ToString("d")} {SelectedTime}";

        public MainWindow()
        {
            InitializeComponent();
            DataContext = this;

            // Generate ComboBox items for time
            for (int hour = 0; hour < 24; hour++)
            {
                string time = $"{hour:D2}:00"; // Format as HH:00
                TimePicker.Items.Add(time);
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}