Castle Windsor Dependency Injection - restore dependencies for existing instance

Question

I have a fairly straight-forward scenario that I am trying to solve but I'm hitting a few brick walls with Windsor - perhaps I'm trying to solve the problem in wrong way?

I have a type called Foo as follows:

public class Foo
{
    [NonSerialized]
    private IBar bar;

    public IBar Bar
    {
        get { return this.bar; }
        set { this.bar = value; }
    }

    public Foo(IBar bar)
    {
    }
}

I instantiate via the container in the normal way:

var myFoo = container.Resolve<Foo>();

The dependency IBar is registered with the container and gets resolved when the object is created. Now that the type has been created, I need to serialize it and I don't want to serialize IBar so it's marked with a NonSerialized attribute.

I then need to deserialize the object and return it to it's former state. How do I achieve this with Castle Windsor? I already have an instance, it is just missing it's dependencies.

If I was using Unity, I would use BuildUp() to solve the problem, but I want to use Castle Windsor in this case.

Elmer

Answer 1

It seems like Foo is having multiple concerns. Try to separate the data part from the behavior by creating a new class for the data and use it as a property in the Foo class:

[Serializable]
public class FooData
{
}

public class Foo
{
    private FooData data = new FooData();

    public IBar Bar { get; private set; }

    public FooData Data { get; set; }

    public Foo(IBar bar)
    {
    }
}

When you have this construct in place you can deserialize FooData and use it in a created Foo:

var foo = container.Get<Foo>();
foo.Data = DeserializeData();

Nickinickie

There is no FooData, there is only Bar. Bar can't be serialized. Bar doesn't even need to be exposed but it must be restored when the object is deserialized. – Elmer

There is no FooData yet. But you are going to create it; that's what I'm saying ;-) – Nickinickie

I'm not following you! IBar is probably a repository which Foo uses to load/save data. How doe I get my repository, or Bar, back into Foo post-deserialize? – Elmer

@Steve: If you look at the last two lines of code in my answer, you see that Foo never gets serialized. You retrieve a new instance of Foo from the container and assign a deserialized FooData to it. If that doesn't work for you, please update your question with some more information. I bet that object is not called Foo but something like ShipOrderCommand? – Nickinickie

You are correct, Foo is something like an Order business object and Bar is an OrderRepository. I need to serialize/deserialize the stateful Order information, and then restore stateless dependencies such as repositories. – Elmer

The FAQ: stw.castleproject.org/… – Amerind

That's very clear - Windsor does not inject dependencies into existing instances. – Elmer