David Hayden has a post about the issue that you face when you are trying to use dependency injection in Web Forms MVC. I talked about similar issues here.
He points out that this type of code is bad:
protected Page_PreInit(object sender, EventArgs e)
{
// Constructor Injection of Data Access Service and View
ICustomerDAO dao = Container.Resolve<ICustomerDAO>():
_presenter = new AddCustomerPresenter(dao, this);
// Property Injection of Logging
ILoggingService logger = Container.Resolve<ILoggingService>():
_presenter.Logger = logger;
}
This type of code a Worst Practice in my opinion. It means that the view is responsible for setting up the presenter, that is a big No! right there.
He gives the example of WCSF & Object Builder way of doing it, but I don't think that this is a good approach:
public partial class AddCustomer : Page, IAddCustomer
{
private AddCustomerPresenter _presenter;
[CreateNew]
public AddCustomerPresenter Presenter
{
set
{
this._presenter = value;
this._presenter.View = this;
}
}
// ...
}
The problems that I have with this approach is that the view suddenly makes assumptions about the life cycle of the controller, which is not something that I want it to do. I may want a controller per conversation, for instance, and then where would I be? Another issue is that the view is responsible for injecting itself to presenter, which is not something that I would like to see there as well.
Here is how I do it with Rhino.Igloo:
public partial class AddCustomer : BasePage, IAddCustomer
{
private AddCustomerPresenter _presenter;
public AddCustomerPresenter Presenter
{
set
{
this._presenter = value;
}
}
// ...
}
The BijectionFacility will notice that we have a settable property of type that inherit from BaseController, and will get it from the container and inject that in. I don't believe in explicit Controller->View communication, but assuming that I needed that, it would be very easy to inject that into the presenter. Very easy as in adding three lines of code to ComponentRepository's InjectControllers method:
PropertyInfo view = controller.GetType().GetProperty("View");
if(view!=null)
view.SetValue(controller, instance);
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