Avalonia/samples/ControlCatalog/Pages/TabbedPage/TabbedPageFirstLookPage.xaml.cs

using System.Collections;
using Avalonia.Controls;
using Avalonia.Interactivity;

namespace ControlCatalog.Pages
{
    public partial class TabbedPageFirstLookPage : UserControl
    {
        private int _tabCounter = 3;

        public TabbedPageFirstLookPage()
        {
            InitializeComponent();
        }

        private void OnAddTab(object? sender, RoutedEventArgs e)
        {
            var idx = ++_tabCounter;
            var page = new ContentPage
            {
                Header = $"Tab {idx}",
                Content = new StackPanel
                {
                    Margin = new Avalonia.Thickness(16),
                    Spacing = 8,
                    Children =
                    {
                        new TextBlock
                        {
                            Text = $"Tab {idx}",
                            FontSize = 24,
                            FontWeight = Avalonia.Media.FontWeight.Bold
                        },
                        new TextBlock
                        {
                            Text = $"This tab was added dynamically (tab #{idx}).",
                            Opacity = 0.7,
                            TextWrapping = Avalonia.Media.TextWrapping.Wrap
                        }
                    }
                }
            };

            ((IList)DemoTabs.Pages!).Add(page);
            UpdateStatus();
        }

        private void OnRemoveTab(object? sender, RoutedEventArgs e)
        {
            var pages = (IList)DemoTabs.Pages!;
            if (pages.Count > 1)
            {
                pages.RemoveAt(pages.Count - 1);
                UpdateStatus();
            }
        }

        private void OnPlacementChanged(object? sender, SelectionChangedEventArgs e)
        {
            if (DemoTabs == null) return;
            DemoTabs.TabPlacement = PlacementCombo.SelectedIndex switch
            {
                1 => TabPlacement.Bottom,
                2 => TabPlacement.Left,
                3 => TabPlacement.Right,
                _ => TabPlacement.Top
            };
        }

        private void OnSelectionChanged(object? sender, PageSelectionChangedEventArgs e)
        {
            UpdateStatus();
        }

        private void UpdateStatus()
        {
            if (StatusText == null) return;
            var pages = (IList)DemoTabs.Pages!;
            var pageName = (DemoTabs.SelectedPage as ContentPage)?.Header?.ToString() ?? "—";
            StatusText.Text = $"{pages.Count} tab{(pages.Count != 1 ? "s" : "")} | Selected: {pageName} ({DemoTabs.SelectedIndex})";
        }
    }
}