LogViewerControl/CSharp/Controls/LogViewer.Avalonia/LogViewerControl.axaml.cs

using System.Collections.Specialized;
using Avalonia.Controls;
using Avalonia.LogicalTree;
using LogViewer.Core;

namespace LogViewer.Avalonia;

public partial class LogViewerControl : UserControl
{
    public LogViewerControl()
        => InitializeComponent();

    private ILogDataStoreImpl? vm;
    private LogModel? item;
  
    private void OnDataContextChanged(object? sender, EventArgs e)
    {
        if (DataContext is null)
            return;

        vm = (ILogDataStoreImpl)DataContext;
        vm.DataStore.Entries.CollectionChanged += OnCollectionChanged;
    }

    private void OnCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
        => item = MyDataGrid.Items.Cast<LogModel>().LastOrDefault();

    private void OnLayoutUpdated(object? sender, EventArgs e)
    {
        if (CanAutoScroll.IsChecked != true || item is null)
            return;

        MyDataGrid.ScrollIntoView(item, null);
        item = null;
    }

    private void OnDetachedFromLogicalTree(object? sender, LogicalTreeAttachmentEventArgs e)
    {
        if (vm is null) return;
        vm.DataStore.Entries.CollectionChanged -= OnCollectionChanged;
    }
}