Registration with Async Instance Creator Factory method

Ideally I’d like a Register overload like the following:

Register<TService>(Func<Task<TService>> instanceCreator, Lifestyle lifestyle)

So I could write the following:

container.Register<SqlConnection>(async () =>
{
     var cn = new SqlConnection("myConnString");
     await cn.OpenAsync();
     return cn;
},
Lifestyle.Scoped);

Would this feature make sense for Simple Injector?

[BrettJaner]

Yup that makes sense. Thanks for the explanation. I’d like to inject the same open connection into all my objects per request and have the container worry about managing the lifetime. So would you suggest my SqlConnectionProvider implement IDisposable and look something like below?

public class SqlConnectionProvider : IDisposable
{
    private readonly Lazy<Task<SqlConnection>> _sqlConnection;

    public SqlConnectionProvider(string connectionString)
    {
        _sqlConnection = new Lazy<Task<SqlConnection>>(async () =>
        {
            var cn = new SqlConnection(connectionString);
            await cn.OpenAsync();
            return cn;
        });
    }

    public Task<SqlConnection> GetConnectionAsync() => _sqlConnection.Value;

    public void Dispose()
    {
        if (_sqlConnection.IsValueCreated)
            _sqlConnection.Value.Result.Dispose();
    }
}

[dotnetjunkie]

btw, you can also let Simple Injector manage the lifetime of the SqlConnection; this prevents you from having to dispose it. But to be honest, I’m not sure that would make the solution more elegant. But just for completeness, here’s how to do it:

// Simplified SqlConnectionProvider implementation
public class SqlConnectionProvider
{
    private readonly Func<Task<SqlConnection>> _provider;
    public SqlConnectionProvider(Func<Task<SqlConnection>> provider) => _provider = provider;
    public Task<SqlConnection> Connection => _provider();
}

// configuration
var connectionProvider = (InstanceProducer<SqlConnection>)Lifestyle.Scoped.CreateProducer(
    () => new SqlConnection(connectionString), container);

var openConnectionTaskProducer = 
    (InstanceProducer<Lazy<Task<SqlConnection>>>)Lifestyle.Scoped.CreateProducer(() =>
        new Lazy<Task<SqlConnection>>(async () => {
            var cn = connectionProvider.GetInstance();
            await cn.OpenAsync();
            return cn;
        }), container);

container.RegisterSingleton(
    new SqlConnectionProvider(() => openConnectionTaskProducer.GetInstance().Value));