How to get Simple injector to auto resolve interface when it only has one concrete?

Question

Currently i have a webapi controller with the constructor like this:

readonly IQueryFactory queryFactory;
readonly ICommandFactory commandFactory;

public UserBenefitsController(
    IQueryFactory queryFactory, 
    ICommandFactory commandFactory)
{
    this.queryFactory = queryFactory;
    this.commandFactory = commandFactory;
}

I am using simple injector to register both of these types.

container.RegisterWebApiRequest<IQueryFactory, QueryFactory>();
container.RegisterWebApiRequest<ICommandFactory, CommandFactory>();

But i am finding that as i continue to develop my app that I am continuing to have a lot of ISomeInterface resolving to ISomeConcrete with 1:1 ratio.

Is it possible to tell simple injector to look for at an interface and automatically resolve it when there is only 1 concrete for it within the WebApiRequest scope?

Answer 1

You can use batch / automatic registration to resolve to concrete instances. The Simple Injector documentation explains it here

For instance:

ScopedLifestyle scopedLifestyle = new WebApiRequestLifestyle();

var assembly = typeof(YourRepository).Assembly;

var registrations =
    from type in assembly.GetExportedTypes()
    where type.Namespace == "Acme.YourRepositories"
    where type.GetInterfaces().Any()
    select new
    {
        Service = type.GetInterfaces().Single(),
        Implementation = type
    };

foreach (var reg in registrations)
    container.Register(reg.Service, reg.Implementation, scopedLifestyle);