private static void AddNamedServiceImpl <TService, TImplementation>(IServiceCollection serviceCollection, string name, ServiceLifetime lifetime)
where TImplementation : class
{
ServiceDescriptor descriptor = serviceCollection.LastOrDefault(x => x.ServiceType == typeof(NamedServiceFactory <TService>));
var factory = descriptor?.ImplementationInstance as NamedServiceFactory <TService>;
if (factory is null)
{
factory = new NamedServiceFactory <TService>();
serviceCollection.AddSingleton(factory);
}
factory.Register <TImplementation>(name);
// We don't want to register using the service descriptor since that would mean multiple TService types
// would be registered causing resolution problems for non-named registrations.
switch (lifetime)
{
case ServiceLifetime.Singleton:
serviceCollection.AddSingleton <TImplementation>();
break;
case ServiceLifetime.Scoped:
serviceCollection.AddScoped <TImplementation>();
break;
case ServiceLifetime.Transient:
serviceCollection.AddTransient <TImplementation>();
break;
}
}
/// <summary>
/// Returns an instance of the service type matching the given name.
/// </summary>
/// <typeparam name="TService">The type of service to return.</typeparam>
/// <param name="provider">The service provider for retrieving service objects.</param>
/// <param name="name">The name the service type is registered as.</param>
/// <returns>The <see cref="TService"/>.</returns>
public static TService GetNamedService <TService>(this IServiceProvider provider, string name)
{
NamedServiceFactory <TService> factory = provider.GetServices <NamedServiceFactory <TService> >().LastOrDefault();
if (factory is null)
{
throw new InvalidOperationException($"No service for type {typeof(TService)} named '{name}' has been registered.");
}
return(factory.Resolve(provider, name));
}