public void WhenActivationDelegateReturnsNull_ExceptionDescribesLimitType()
{
var target = new DelegateActivator(typeof(string), (c, p) => null);
var ex = Assert.Throws<DependencyResolutionException>(
() => target.ActivateInstance(new ContainerBuilder().Build(), Enumerable.Empty<Parameter>()));
Assert.That(ex.Message.Contains(typeof(string).ToString()));
}
public void ActivateInstance_ReturnsResultOfInvokingSuppliedDelegate()
{
var instance = new object();
var target =
new DelegateActivator(typeof(object), (c, p) => instance);
Assert.AreSame(instance, target.ActivateInstance(new ContainerBuilder().Build(), Enumerable.Empty<Parameter>()));
}
/// <summary>
/// Retrieve registrations for an unregistered service, to be used
/// by the container.
/// </summary>
/// <param name="service">The service that was requested.</param>
/// <param name="registrationAccessor">A function that will return existing registrations for a service.</param>
/// <returns>Registrations providing the service.</returns>
public IEnumerable<IComponentRegistration> RegistrationsFor(Service service, Func<Service, IEnumerable<IComponentRegistration>> registrationAccessor)
{
if (service == null) throw new ArgumentNullException(nameof(service));
if (registrationAccessor == null) throw new ArgumentNullException(nameof(registrationAccessor));
var swt = service as IServiceWithType;
if (swt != null)
{
var serviceType = swt.ServiceType;
Type elementType = null;
if (serviceType.IsGenericEnumerableInterfaceType())
{
elementType = serviceType.GetTypeInfo().GenericTypeArguments.First();
}
else if (serviceType.IsArray)
{
elementType = serviceType.GetElementType();
}
if (elementType != null)
{
var elementTypeService = swt.ChangeType(elementType);
var elementArrayType = elementType.MakeArrayType();
var listType = typeof(List<>).MakeGenericType(elementType);
var serviceTypeIsList = serviceType.IsGenericListOrCollectionInterfaceType();
var activator = new DelegateActivator(
elementArrayType,
(c, p) =>
{
var elements = c.ComponentRegistry.RegistrationsFor(elementTypeService);
var items = elements.Select(cr => c.ResolveComponent(cr, p)).ToArray();
var result = Array.CreateInstance(elementType, items.Length);
items.CopyTo(result, 0);
return serviceTypeIsList ? Activator.CreateInstance(listType, result) : result;
});
var registration = new ComponentRegistration(
Guid.NewGuid(),
activator,
new CurrentScopeLifetime(),
InstanceSharing.None,
InstanceOwnership.ExternallyOwned,
new[] { service },
new Dictionary<string, object>());
return new IComponentRegistration[] { registration };
}
}
return Enumerable.Empty<IComponentRegistration>();
}
