HC_APTBS/Views/Pages/DeveloperPage.xaml.cs

using System.Collections.Specialized;
using System.Windows.Controls;
using HC_APTBS.ViewModels.Pages;

namespace HC_APTBS.Views.Pages
{
    /// <summary>
    /// Code-behind for the Developer Tools page. Auto-scrolls the log to the
    /// bottom when entries are appended so the latest TX/RX is always visible.
    /// Compiled into Debug builds only — see <c>HC_APTBS.csproj</c>.
    /// </summary>
    public partial class DeveloperPage : UserControl
    {
        private DeveloperPageViewModel? _vm;

        public DeveloperPage()
        {
            InitializeComponent();
            DataContextChanged += OnDataContextChanged;
        }

        private void OnDataContextChanged(object sender, System.Windows.DependencyPropertyChangedEventArgs e)
        {
            if (_vm is { } old)
                ((INotifyCollectionChanged)old.Log).CollectionChanged -= OnLogChanged;

            _vm = DataContext as DeveloperPageViewModel;

            if (_vm is not null)
                ((INotifyCollectionChanged)_vm.Log).CollectionChanged += OnLogChanged;
        }

        private void OnLogChanged(object? sender, NotifyCollectionChangedEventArgs e)
        {
            if (e.Action == NotifyCollectionChangedAction.Add)
                Dispatcher.BeginInvoke(() => LogScroller.ScrollToBottom());
        }
    }
}