Dynamic ViewModel

MVVM without source generation, for data whose shape is only known at runtime.

You learn: DynamicViewModel, IDynamicProperty<T>, a plain MonoView with binders listed by id.

Assumes: Counter.

Script: Scripts/StopwatchBootstrap.cs. Scene: Scenes/Dynamic ViewModel.unity.

When you need it

Properties come from a config, a server or a level editor, and there is no [ViewModel] class to write for them. DynamicViewModel declares properties by a string id, and binders find them by the same id.

Stopwatch

public sealed class StopwatchBootstrap : MonoBehaviour
{
    [SerializeField] private MonoView _view;

    private IDynamicProperty<string> _elapsed;
    private IDynamicProperty<int> _laps;

    private void Awake()
    {
        var viewModel = new DynamicViewModel();

        viewModel.Add("Title", "Stopwatch", BindMode.OneTime);
        _elapsed = viewModel.Add("Elapsed", Format(0f));
        _laps = viewModel.Add("Laps", 0);

        viewModel.Add<IRelayCommand>("LapCommand", new RelayCommand(() => _laps.Value++), BindMode.OneTime);

        _view.Initialize(viewModel);
    }

    private void Update()
    {
        if (!_isRunning) return;

        _seconds += Time.deltaTime;
        _elapsed.Value = Format(_seconds);
    }
}

Add<T>(id, value, mode) returns an IDynamicProperty<T>, the handle used to read and write the value. Binders follow it.
The default mode is OneWay. Commands and constants are fine with OneTime.
A command is just another value: Add<IRelayCommand>(...).

View without a class

The scene has a plain MonoView. Its Binders list maps each id (Title, Elapsed, Laps, LapCommand, …) to binders and a value type. No [View], no [ViewModel], no generator.

What you give up

The analyzer: a typo in "Elapsd" is found at runtime, not at compile time.
Type checks at the boundary: Add("Laps", 0) and a binder typed string disagree on the first value.

DynamicViewModel is for truly dynamic data, not a way to save one class.

When you need it​

Stopwatch​

View without a class​

What you give up​

When you need it

Stopwatch

View without a class

What you give up