VContainer + UniTask

UniTask is a library that brings fast and powerful async/await to the Unity world.

If you have the com.cysharp.unitask package installed in your project, the following features will be enabled.

IAsyncStartable#

We can create an entry point for the async UniTask.

public class FooController : IAsyncStartable
{
    public async UniTask StartAsync(CancellationToken cancellation)
    {
        await LoadSomethingAsync(cancellation);
        await ...
        ...
    }
}

By creating a class like the one above and Registering it, the UniTask of StartAsync will be executed automatically.

builder.RegisterEntryPoint<FooController>(Lifetime.Scoped);

For more information about RegisterEntryPoint, please check here.

StartAsync() timing#

The only async interface provided by VContainer is IAsyncStartable. UniTask can control the execution timing within the async method.

If you want to schedule the process at different times, you can use UniTask's PlayerLoopTiming.

await UniTask.Yield(PlayerLoopTiming.FixedUpdate);

See https://github.com/Cysharp/UniTask#playerloop

Exception Handling#

Within the async method, try/catch can be used.
We can use UniTaskScheduler.UnobservedTaskException event.
Alternatively, if you want to register a separate error handler for each LifetimeScope, use:
- builder.RegisterEntryPointExceptionHandler(ex => ..)
- See the Entry point section for more information.

CancellationToken#

The argument of StartAsync will be a cancellationToken.

This cancellationToken will be canceled when the LifetimeScope is destroyed.

Async asset loading#

UniTask supports the ability to load assets and scenes asynchronously. This is useful when used with LifetimeScope.Enqueue* in VContainer.

var extraAsset = await Addressables.LoadAssetAsync<ExtraAsset>(key);

using (LifetimeScope.EnqueueParent(parentScope))
using (LifetimeScope.Enqueue(builder => builder.RegisterInstance(extraAsset))
{
    await SceneManager.LoadSceneAsync("AdditiveScene");
}

See Scoping secion for more information.