Compose Unity UI components in C#

A component is an ordinary C# function returning a Unity component.

UnityEngine.UI.Button IncrementButton(Source<int> count)
{
    return UI.Button("Increment", () => count.Value++,
        UI.PreferredSize(320, 48));
}

Call builders under a mount/root. Returned components can be direct child properties:

var count = UI.Source(0);
var panel = UI.Column(
    UI.Label(() => $"Count: {count.Value}"),
    IncrementButton(count));

Frame, Column, Row, Label, Image and Button are convenience builders. Create<T> exposes other native components. Fixed/reactive Children overloads compose returned components or GameObjects; reactive children reconcile membership and sibling order.

Properties

Property is the shared type for configuration operations. Typed values and setters configure the native components attached to each GameObject.

var text = UI.Label("Welcome",
    UI.FontSize(28),
    UI.Configure<TMPro.TextMeshProUGUI>(t =>
        t.alignment = TMPro.TextAlignmentOptions.Center));

Configure runs once. Set<T,TValue> accepts literals, explicit reactive values or direct getter lambdas. Static values apply once; dynamic getters run in effects. Setters do not collect extra dependencies. Group composes properties, with configurable ordering.

Create and Clone own their objects; Apply binds an external object without owning it. Removing a child detaches it; its creation scope owns destruction. Avoid independent bindings that compete to write the same property.

Events and controls

OnClick, On<T> and On<T,TValue> subscribe native events with scoped cleanup. Later callbacks run untracked in a batch. Changed uses a supplied event or polls only the observed property.

InputValue, ToggleValue and SliderValue provide two-way bindings using notification-free setters. Apply them to native controls configured with child graphics, handles and text viewports.

Continue with dynamic UI.