VContainer + UniTask

UniTask is a library that brings fast and powerful async/await support to Unity. Its API is nearly identical to that of .NET's standard Task-based asynchronous pattern, but optimized for Unity's player loop. It also adds async/await support for Unity's built-in asynchronous operations such as UnityWebRequest.

If you have the com.cysharp.unitask package installed in your project, The VCONTAINER_UNITASK_INTEGRATION compiler symbol is automatically enabled and the following features will automatically be enabled.

IAsyncStartable

If VCONTAINER_UNITASK_INTEGRATION is enabled, IAsyncStartable uses UniTask as return value.

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

Once a class that implements IAsyncStartable is registered its StartAsync method will be executed automatically, similarly to IStartable.

builder.RegisterEntryPoint<FooController>();

For more information about RegisterEntryPoint, see here.

StartAsync() timing

Currently, the only async interface provided by VContainer is IAsyncStartable. If you need to execute async code in different PlayerLoop phases, UniTask itself provides ways to control the execution timing within the method.

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

await UniTask.Yield(PlayerLoopTiming.FixedUpdate);

Note that all StartAsync calls will be scheduled for simultaneous execution on the main thread (unless otherwise specified within each implementation), and future PlayerLoop phases will not wait for them to complete.

See UniTask's PlayerLoop documentation for more information.

Exception Handling

• Unlike IEnumerator-backed coroutines, async methods fully support try/catch/finally statements.
• You can use the 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

StartAsync is provided with a CancellationToken that is canceled when the LifetimeScope that registered it is destroyed.

Async Asset Loading

UniTask offers the ability to load assets and scenes asynchronously. This is helpful when used with one of VContainer's LifetimeScope.Enqueue* methods.

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

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

See the Scoping section for more information.