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How Can I Resolve Other Dependencies within Ninject .OnActivation?

I am using Ninject to set up bindings for a class which is an IObservable.
I have set up a rebind to ensure that the IObservable has it's IObserver subscribed as follows...
kernel.Rebind<IAddressRepository>().To<AddressRepository>().InRequestScope()
.OnActivation(repo => repo
.Subscribe(new SyncTrackerDataEventObserver<Address, AddressRepository>()));
This seems to work OK but it really isn't ideal. SyncTrackerDataEventObserver will, when it's more than a stub have dependencies of it's own. Then we end up with this...
kernel.Rebind<IAddressRepository>().To<AddressRepository>().InRequestScope()
.OnActivation(repo => repo
.Subscribe(new SyncTrackerDataEventObserver<Address, AddressRepository>(new SyncTrackerRepository(new SyncDataSource))));
Ouch!!
What I want to do is make use of the existing bindings at this point. I'd expect to be able to write something like this (but this is just made up..)
kernel.Rebind<IAddressRepository>().To<AddressRepository>().InRequestScope()
.OnActivation(repo => repo
.Subscribe(kernel.Resolve<ISyncTrackerDataEventObserver>()));
What is the correct way to achieve this without creating a hell of hard coded dependencies and breaking IoC paradigms?

This was quite straightforward when I figured out where to look. kernel.TryGet<> will get you the service type from the current bindings.
kernel.Rebind<IAddressRepository>().To<AddressRepository>().InBackgroundJobScope()
.OnActivation(repo => repo
.Subscribe(kernel.TryGet<SyncTrackerDataEventObserver<Address, AddressRepository>>()
?? throw new ObserverBindingException("Address")));
(where ObserverBindingException is a custom exception type I created just for this purpose).

Define global BeforeMap and AfterMap callbacks for AutoMapper

I know about the feature of defining a Before/AfterMap callback on the map level for a given type pair. However, I'm searching for a solution to define a global Before/AfterMap function somehow, which would apply to every defined type map.
In most of my DTOs I have a mechanism which prevents changed notifications temporarly with the BeginUpdate/EndUpdate pattern. I would like AutoMapper to wrap the mapping between these calls whenever the target type supports it.
I've looked through questions here and the AutoMapper docs but haven't found a native solution.

I think I've found a porposed solution, but haven't tested it completely yet.
After all of my maps are registered, I would do something like this:
var typeMaps = Mapper.GetAllTypeMaps();
foreach (var typeMap in typeMaps)
{
typeMap.AddBeforeMapAction(...);
typeMap.AddAfterMapAction(...);
}

Can I use AutoMapper to map between two fields which are immutable?

I have the following two classes (many properties elided for brevity).
Service Layer POCO:
public class TicketFlag
{
public ContactKey ContactKey;
}
LINQ to SQL generated POCO:
public class TicketFlag
{
public string ContactKey;
}
When trying to use AutoMapper to map between these two on service calls -> database save, I'm getting the following exception:
Exception of type 'AutoMapper.AutoMapperMappingException' was thrown.
---> System.ArgumentException: Type 'ContactKey' does not have a default constructor
ContactKey does not have a default constructor on purpose. Basically, it takes a string and a list of objects and can serialize/deserialize itself.
I have tried creating a mapping function (and it's inverse) like so:
Mapper.CreateMap<string, ContactKey>().ConvertUsing(s => ContactKeySerializer.Serialize(s));
But I'm still getting complaints because ContactKey doesn't have a default constructor.
Is there a way to get AutoMapper to not use the default constructor to do it's property mapping? Really, just mapping properties on the ContactKey isn't sufficient - I need to have it call the constructor, or get spit out from my ContactKeySerializer class.

First, you should probably be using properties for these things, not fields. However, I doubt that's part of your problem.
Instead of trying to create a map from string to ContactKey, you could try to make this part of the map from one TicketFlag to the other:
Mapper.CreateMap<LINQtoSQL.TicketFlag, Service.Layer.TicketFlag>()
.ForMember(dest => dest.ContactKey,
mem => mem.ResolveUsing(src => ContactKeySerializer.Serialize(src.ContactKey)));
I think that would prevent the error you're getting.

AutoMapper is complaining that you don't have a default constructor because AutoMapper needs to create an empty instance of the target class before it can map values to it. It can't call your ContractKey's parameterized constructor - how would it?
In this case it might seem simple, if the constructor looks like this:
public ContracktKey(string keyValue){}
But what if it had two parameters?
public ContracktKey(string keyValue, string otherValue){}
How would it know where to put the value? What if you only provided one string?
I think it would be best to follow others' advice and map the two TicketFlag objects.

Having Automapper use services constructed by a Autofac with WebApi

I'm using WebAPI + Autofac + Automapper, with a repository for data access. I need to map a model to my domain entities, specifically, I need to convert an identity value to the actual entity. No big deal, right? I've done this in MVC with no problem. I will simplify what I am doing to expose the essentials.
public class EntityConverter<T> : ITypeConverter<int, T>
where T : Entity
{
public EntityConverter(IRepository<T> repository)
{
_repository = repository;
}
private readonly IRepository<T> _repository;
public T Convert(ResolutionContext context)
{
_repository.Get((int) context.SourceValue);
}
}
Repositories are registered with Autofac, and are managed as InstancePerApiRequest because of session/transaction management. So, I need to register my converter in that same scope:
builder.RegisterGeneric(typeof(EntityConverter<>))
.AsSelf()
.InstancePerApiRequest();
The Automapper config looks something like:
var container = builder.Build(); // build the Autofac container and do what you will
Mapper.Initialize(cfg => {
cfg.ConstructServicesUsing(container.Resolve); // nope nope nope
// configure mappings
cfg.CreateMap<int, TestEntity>().ConvertUsing<EntityConverter<TestEntity>>()
});
Mapper.AssertConfigurationIsValid();
So here's the part that sucks. I am to understand Automapper requires the ConstructServicesUsing guy to be set before you build your config. If you set it later, it won't be used. The example above won't work because container is the root scope. If I try and resolve EntityConverter<TestEntity>, Autofac will complain that the requested type is registered for a different scope, and the one you're in ain't it. Makes sense, I want the scope created by WebApi.
Let me pause a sec and cover one fact about WebApi dependency injection (I don't really think this is Autofac-specific). WebApi creates an IDependencyScope for the request, and stashes it in the HttpRequestMessage.Properties. I can't get it back again unless I have access to that same HttpRequestMessage instance. My AsInstancePerApiRequest scoping on IRepository and my converter thus rely on that IDependencyScope.
So, that's really the meat and potatoes of the problem, and I really frustrated with this difference from MVC. You can't do
cfg.ConstructServicesUsing(GlobalConfiguration.Configuration.DependencyResolver.GetService);
That's equivalent to using container.Resolve. I can't use
GlobalConfiguration.Configuration.DependencyResolver.BeginScope().GetService
because A) that creates a new scope next to the one I actually want B) doesn't really let me clean up the new scope I created. Using Service Locator is a new way to have the same problem; I can't get to the scope WebApi is using. If my converter and its dependencies were single instance or instance per dependency, it wouldn't be a problem, but they aren't, so it is, and changing that would create lots more problems for me.
Now, I can create AutoMapper config with Autofac and register it as a single instance. I can even create per-request IMappingEngine instances. But that doesn't do me any good if the service constructor always uses that single delegate you register at the beginning, which has no access to the current scope. If I could change that delegate per each mapping engine instance, I might be in business. But I can't.
So what can I do?

Another option, this time it's built-in, is to use the per-map options:
Mapper.Map<Source, Destination>(dest, opt => opt.ConstructServicesUsing(type => Request.GetDependencyScope().GetService(typeof(YourServiceTypeToConstruct))));
Don't bother with setting up the global IoC config in your mapping configuration.
Another option is to use your IoC tool to configure how to instantiate the MappingEngine:
public MappingEngine(
IConfigurationProvider configurationProvider,
IDictionary<TypePair, IObjectMapper> objectMapperCache,
Func<Type, object> serviceCtor)
The first one is just Mapper.Configuration, the second should probably be a singleton, and the third you can fill in with the current nested container's resolution. This would simplify from having to call the Map overload every time.

Update: Automapper was updated to support that feature. See #Jimmy Bogard 's answer
This solution could be not very nice, but it works. The solution relates to WebAPI 2, I'm not sure about previous versions.
In WebAPI 2 you can get current IDependencyScope from current HttpRequestMessage via GetDependencyScope() extension method. Current HttpRequestMessage is stored in the Items property of the current HttpContext. Knowing that your factory could look like:
Mapper.Initialize(cfg =>
{
cfg.ConstructServicesUsing(serviceTypeToConstruct =>
{
var httpRequestMessage = HttpContext.Current.Items["MS_HttpRequestMessage"] as HttpRequestMessage;
var currentDependencyScope = httpRequestMessage.GetDependencyScope();
return currentDependencyScope.GetService(serviceTypeToConstruct);
});
// configure mappings
// ...
});

This may or may not be suitable for you.. but here goes:
We recently did this.. for model binders in MVC. Our model binders (on GET requests) now use Ninject-managed Services to build models.
Basically, we inject a factory (using Ninject's Factories extension.. perhaps there is a similar one for Autofac) into an "AutomapperBootstrapper" class, which in turn creates Automapper mapping Profile's and adds them to Automapper. Somewhat like this:
Mapper.Initialize(cfg =>
{
cfg.AddProfile(_factory.CreateServiceViewModelMappingProfile());
// etc..
});
The mappings Profile's themselves use MapFrom(), which is evaluated each time a mapping occurs. Something like this:
Mapper.CreateMap<Service, ServiceViewModel>()
.ForMember(x => x.Regions,
opt =>
opt.MapFrom(x => getRegions()))
private IEnumerable<Region> getRegions() {
return _factory.CreateTheService().GetRegions();
}
Each time the model binder is fired up, Ninject still wires up all dependencies for the request and it all filters down.
(For those interested, this setup basically lets us do this: /Area/Controller/Action/12, and our controller action method is this:
[HttpGet]
public ActionResult Action(ServiceViewModel model) {
// ...
}
).

Structure Map 2.6.1

In my current project I'm currently trying to replace the Windsor IoC in favour of structure map (2.6.1). But having a bit of problem registering some generic types. How would I register IFilterConverter<T> to use FilterConverter<SomeSpecificType>. I've tried ConnectImplementationsToTypesClosing(IFilterConverter) but from what I've read (Jimmy Bogard's article) I would need a concrete type defined like so:- SomeConcreteType : IFilterConverter<SomeSpecificType> for that to work and I don't have that.
So to reiterate if I have a type that takes a constructor argument IFilterConverter<SomeSpecificType>, I want structure map to provide me with FilterConverter<SomeSpecificType>.
With Windsor I was using the XML config option (which I want to get away from) But all I did was just set up the configuration like so:
<component id="IFilterConverter" service="SomeNamespace.IFilterConverter`1, SomeNamespace" type="SomeNamespace.FilterConverter`1, SomeNamespace" lifestyle="PerWebRequest">
How do I do the equivalent in SM (using code, not XML config files)
Thanks

I think this should do it.
_container = new Container();
_container.Configure(x =>
{
x.For(typeof (IFilterConverter<>)).Use(typeof (FilterConverter<>));
});