Question

I’m currently trying to work out how to set the initial values for some fields using Ninject.

I have something like this:

public class SomeClass
{
    private ISomething _something;

    public SomeClass(string someParam)
    {

    }

    public void DoAThing()
    {
        _something.DoSomething();
    }
}

My dilemma comes about in the setting of _something to an initial value, given I don’t want the class to know anything about which default implementation of ISomething to use, is there a way of achieving this in Ninject?

I should add that passing the initial values in via the constructor is not an option.

I should also add that this is in a class-library, so any information on how and when the setup of the kernel & injection should take place would be great 🙂

Elaboration: It seems that people could be getting confused, I am not trying to get an ISomething into the class (it isn’t a dependency), rather, the default implementation of ISomething is the dependency, this is why I went for the service-locator pattern, for actual dependencies I would of course have them in the constructor.

Thanks.

Answer 1

Yes, it’s not very good to have highly coupled classes, thus depending on abstractions is a good choice. But hiding your dependencies is not very good solution. Make them visible to clients of your class, and use dependency injection to provide concrete implementations of dependencies to your class:

public class SomeClass
{
    private ISomething _something;

    public SomeClass(ISomething something, string someParam)
    {
        _something = something;
    }

    public void DoAThing()
    {
        _something.DoSomething();
    }
} 

Also consider to create factory, which will provide default implementation of ISomething to created SomeClass objects.