SkeleKit.iOS 0.1.0

SkeleKit.iOS

A WPF-inspired UI library for .NET for iOS - no MAUI, no XAML. Native UIKit controls behind C# object-initializer syntax with AOT-safe MVVM bindings. App code never touches UIViewController, NSLayoutConstraint, or AppDelegate boilerplate.

• Native UIKit, 1:1: wraps the real UIKit controls. SkeleKit owns composition and layout, never rendering.
• Clean C# syntax: Grid, StackPanel, Overlay, Border, Margin, Alignment, MVVM bindings and commands. Element trees via object initializers.
• AOT-safe by construction: device builds are Mono full AOT + trimmed. No reflection, no expression trees, no runtime codegen. Bindings use compiled getters + [CallerArgumentExpression].
• Framework concerns handled: dark mode, Dynamic Type, safe areas, keyboard avoidance.
• No base ViewModel required: works with plain INotifyPropertyChanged / ICommand. CommunityToolkit.Mvvm fits naturally.

Requirements

• macOS with Xcode and the .NET 10 iOS workload
• .NET 10, net10.0-ios, iOS 18+
• No dependencies beyond Microsoft.Extensions.DependencyInjection

Quick start

dotnet new install SkeleKit.Templates
dotnet new skelekit-ios -n MyIosApp
cd MyIosApp
dotnet build -r iossimulator-arm64

The template creates the scene manifest, SkeleKit host, first [Page], launch screen, entitlements, and app-icon catalog. It references SkeleKit.iOS, which also carries the page source generator and the simulator hot-reload build targets.

<details>

<summary>Create project manually</summary>

1. Create the .NET project:

   dotnet new ios -n MyIosApp
   

2. Target iOS 18 or later: set <SupportedOSPlatformVersion>18.0</SupportedOSPlatformVersion> in the project file.

3. Add SkeleKit:

   dotnet add package SkeleKit.iOS
   

4. Use SkeleKit's scene delegate: in Info.plist, set UIApplicationSceneManifest → UISceneConfigurations → UIWindowSceneSessionRoleApplication → item 0 → UISceneDelegateClassName to SkeleWindowSceneDelegate. Delete the generated AppDelegate.cs and SceneDelegate.cs.

5. Create the first page:

   using SkeleKit;
   
   [Page]
   public class MainView : ContentView
   {
       public MainView()
       {
           Content = new Label() { Text = "Hello World!" };
       }
   }
   

6. Replace Main.cs with the SkeleKit host:

   using SkeleKit;
   
   SkeleApplication.CreateBuilder()
        .SinglePage<MainView>()
        .Build()
        .Run(args);
   

</details>

Getting started

The following ViewModel uses the optional CommunityToolkit.Mvvm package; SkeleKit itself does not require a base ViewModel type.

// CounterView.cs
[Page]
public class CounterView : ContentView<CounterViewModel>
{
    public CounterView(CounterViewModel viewModel) : base(viewModel)
    {
        Title = "Counter";

        Content = new StackPanel
        {
            Spacing = 12,
            Padding = new Thickness(16),
          
            Children =
            {
                new Label
                {
                    Text = Bind<int, string?>(vm => vm.Count, count => $"Tapped {count} times"),
                    FontSize = 34,
                    FontWeight = FontWeight.Bold
                },
                new Button
                {
                    Text = "Click me",
                    Kind = ButtonStyle.Filled,
                    Command = viewModel.IncrementCommand
                }
            }
        };
    }
}

// CounterViewModel.cs
public partial class CounterViewModel : ObservableObject
{
    [ObservableProperty]
    public partial int Count { get; set; }

    [RelayCommand]
    void Increment() => Count++;
}

Styling

No ResourceDictionary and no setter system: shared values are plain statics, and a style is a typed action over the control: IntelliSense, compile-time checking, zero reflection.

static class Styles
{
    public static readonly Style<Label> Caption = new(label =>
    {
        label.FontSize = 12;
        label.TextColor = Colors.SecondaryLabel;
    });

    // BasedOn: Card runs first, then the overrides
    public static readonly Style<Border> Card = new(border =>
    {
        border.Background = Colors.SecondaryGroupedBackground;
        border.CornerRadius = 12;
    });
    public static readonly Style<Border> ProminentCard = new(Card, border =>
    {
        border.Shadow = new(opacity: 0.2, radius: 8, offsetY: 4);
    });
}

new Label
{
    Style = Styles.Caption, // explicit: Style goes FIRST, later lines win
    Text = "Runtime"
};

// App-global themes, applied to every view of the type
SkeleApplication.CreateBuilder()
    .UseTheme(theme => theme.Style(new Style<Button>(b => b.Kind = ButtonStyle.Tinted)));

Precedence (each source beats the previous): control defaults → theme (base type first) → explicit Style → the initializer after it.

What's in the box

• Layout: Grid (star/auto/pixel, spans, spacing), StackPanel, Overlay, Border, ScrollView, per-view IgnoresSafeArea. Two-pass measure/arrange engine, unit-testable off-device.
• Controls: Label, Button, Image (async, cached), TextField, SecureField, TextEditor, TextView (rich text + links), Switch, Slider, Stepper, ProgressBar, ActivityIndicator, Divider, Picker<T>, SegmentedControl, DatePicker, PageControl, ColorWell, MapView, WebView, and NativeView as the UIKit escape hatch.
• Lists: virtualized CollectionView<T> over UICollectionView + diffable data source — list (incl. inset-grouped), grid, carousel; sections + headers; pull-to-refresh, swipe actions, context menus, reorder, empty view, live INotifyCollectionChanged updates.
• Bindings: one-way / two-way / one-way-to-source / one-time, converters, update triggers, nested paths, BindingContext inheritance. Background-thread updates marshal to the UI thread.
• Navigation: ViewModel-first INavigator — push/pop, modals + sheets (detents), alert / confirm / action sheet. Shells via Tabs(...), Stack<T>(), or SinglePage<T>(); tab apps can opt into an iPad sidebar with .OnPad(pad => pad.Sidebar()).
• Visual & animation: Brush (solid / gradient / material), Shadow, CornerRadius; Animation + an interruptible, scrubbable Animator.
• Styling: typed Style<T> with BasedOn, an app-global Theme, Label.TextStyle.
• System integration: dark mode, Dynamic Type, VoiceOver, haptics, keyboard avoidance, gestures.

Repository layout

Escape hatches

UIKit is never required, but always reachable: wrap any UIView with NativeView, reach the native control via view.Native, the hosting controller via ContentView.Controller, or attach a UIGestureRecognizer with view.AddGesture(...).