AudioProgramConfigWindow.xaml.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Diagnostics;

namespace MultiDisplay
{
    public partial class AudioProgramConfigWindow : Window, INotifyPropertyChanged
    {
        private string programName;
        private AudioDeviceViewModel selectedDevice;
        private int processId;

        public string ProgramName
        {
            get => programName;
            set
            {
                programName = value;
                OnPropertyChanged();
            }
        }

        public ObservableCollection<AudioDeviceViewModel> AudioDevices { get; }

        public AudioDeviceViewModel SelectedDevice
        {
            get => selectedDevice;
            set
            {
                selectedDevice = value;
                OnPropertyChanged();
            }
        }

        public AudioProgramConfigWindow(string programName, int processId, ObservableCollection<AudioDeviceViewModel> audioDevices)
        {
            InitializeComponent();
            DataContext = this;
            ProgramName = programName;
            this.processId = processId;
            AudioDevices = audioDevices;

            var defaultDevice = audioDevices.FirstOrDefault();
            if (defaultDevice != null)
            {
                SelectedDevice = defaultDevice;
            }
        }

        private void ApplyButton_Click(object sender, RoutedEventArgs e)
        {
            if (SelectedDevice == null)
            {
                MessageBox.Show("Please select an audio device.", "Error", 
                    MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            try
            {
                AudioDeviceManager.ChangeAppAudioDevice((uint)processId, SelectedDevice.DeviceId);

                MessageBox.Show(
                    $"Audio device for {ProgramName} has been set to {SelectedDevice.FriendlyName}",
                    "Success",
                    MessageBoxButton.OK,
                    MessageBoxImage.Information);

                DialogResult = true;
            }
            catch (Exception ex)
            {
                MessageBox.Show(
                    $"Failed to change audio device: {ex.Message}",
                    "Error",
                    MessageBoxButton.OK,
                    MessageBoxImage.Error);
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}