Avalonia/samples/ControlCatalog/Pages/TabControlPage.xaml.cs

using System;

using Avalonia;
using Avalonia.Controls;
using Avalonia.Markup.Xaml;
using Avalonia.Media.Imaging;
using Avalonia.Platform;

using ReactiveUI;

namespace ControlCatalog.Pages
{
    using System.Collections.Generic;

    public class TabControlPage : UserControl
    {
        public TabControlPage()
        {
            InitializeComponent();

            DataContext = new PageViewModel
            {
                Tabs = new[]
                {
                    new TabItemViewModel
                    {
                        Header = "Arch",
                        Text = "This is the first templated tab page.",
                        Image = LoadBitmap("avares://ControlCatalog/Assets/delicate-arch-896885_640.jpg"),
                    },
                    new TabItemViewModel
                    {
                        Header = "Leaf",
                        Text = "This is the second templated tab page.",
                        Image = LoadBitmap("avares://ControlCatalog/Assets/maple-leaf-888807_640.jpg"),
                    },
                    new TabItemViewModel
                    {
                        Header = "Disabled",
                        Text = "You should not see this.",
                        IsEnabled = false,
                    },
                },
                TabPlacement = Dock.Top,
            };
        }

        private void InitializeComponent()
        {
            AvaloniaXamlLoader.Load(this);
        }

        private IBitmap LoadBitmap(string uri)
        {
            var assets = AvaloniaLocator.Current.GetService<IAssetLoader>();
            return new Bitmap(assets.Open(new Uri(uri)));
        }

        private class PageViewModel : ReactiveObject
        {
            private Dock _tabPlacement;

            public TabItemViewModel[] Tabs { get; set; }

            public Dock TabPlacement
            {
                get { return _tabPlacement; }
                set { this.RaiseAndSetIfChanged(ref _tabPlacement, value); }
            }
        }

        private class TabItemViewModel
        {
            public string Header { get; set; }
            public string Text { get; set; }
            public IBitmap Image { get; set; }
            public bool IsEnabled { get; set; } = true;           
        }
    }
}