Using Unity to call a static injection method

Question

We have a class (in fact many) that have a static initialization function that it needs to carry out on an object within the dependency injection container (using Unity).

public class MyClass
{
    public static void InitializeMappings(IMapper mapper)
    {
        // Do stuff to mapper
    }
}

I would like the InitializeMappings function to be called whenever a new IMapper instance is instantiated by the Unity container.

I need help to:

Call the InitializeMappings function from the container
Resolve the mapper parameter for the function call
Connect up the call to InitializeMappings to the lifetime of IMapper implementations

How would I go about implementing/defining this?

It's a static method. You can easily call it yourself once during app startup. — Steven
– Steven, Commented Apr 15, 2013 at 8:28
@Steven - But then how do I bind the static function to the lifetime of the container item (that is, the IMapper)? — Reddog
– Reddog, Commented Apr 15, 2013 at 23:02

Chris Tavares · Accepted Answer · 2013-04-17 19:55:51Z

5

This is bad design; why not have the mapper implementations call the setup function in their constructors directly?

You can get the container to do this, either through an extension, or by using an injection factory. Something like this:

container.RegisterType<IMapper>(
    new WhateverLifetimeYouWant(),
    new InjectionFactory(
        c => {
            var mapper = c.Resolve<IMapper>("RealMapper");
            MyClass.InitializeMappings(mapper);
            return mapper;
        }
)
.RegisterType<IMapper, ActualMapper>("RealMapper");

Then whenever you do container.Resolve<IMapper>() it'll run that little chunk of code.

This only works through the API, not through config files.

answered Apr 17, 2013 at 19:55

Chris Tavares

30.6k4 gold badges49 silver badges66 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Reddog Over a year ago

My mapper implementation was a class I didn't have access to. However, in hindsight I should have wrapped it up and done as you suggest at the top - by calling them in the constructor. But this approach only holds in the case where the number of mapper implementations is controlled. The injection factory idea worked great though. Thanks!

Nigel Thorne · Accepted Answer · 2013-04-16 06:08:42Z

2

In WPF I believe you can do the following

container.RegisterType<Mapper, Mapper>();
container.Register<IMapper>(
    new InjectionFactory(c => {
        var mapper = c.Resolve<Mapper>(); 
        MyClass.InitializeMappings(mapper);
        return mapper;
    })
);

As far as "Connect up the call to the lifetime of the IMapper" I don't get what you mean. Any objects created and only referenced by the mapper object would be garbage collected when the mapper object was.

answered Apr 16, 2013 at 6:08

Nigel Thorne

21.6k3 gold badges38 silver badges53 bronze badges

Collectives™ on Stack Overflow

Using Unity to call a static injection method

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related