presence/Presence.Desktop/Views/PresenceView.axaml.cs

using System.Linq;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Markup.Xaml;
using Avalonia.ReactiveUI;
using Presence.Desktop.Models;
using Presence.Desktop.ViewModels;
using ReactiveUI;

namespace Presence.Desktop.Views;

public partial class PresenceView : ReactiveUserControl<PresenceViewModel>
{
    public PresenceView()
    {
        this.WhenActivated(disposables => { });
        AvaloniaXamlLoader.Load(this);    
    }
    
    private void OnAttendanceSelectionChanged(object? sender, SelectionChangedEventArgs e)
    {
        if (DataContext is PresenceViewModel vm && sender is DataGrid grid)
        {
            vm.SelectedAttendanceRecords = grid.SelectedItems
                .OfType<UserPresencePresenter>()
                .ToList();
        }
    }
}