Dependency Injector NINJECT

Hello

Stuff, i learned recently

For example, there is peace of code:

public partial class MainWindow : Window

{

ISubject _subject;

public MainWindow()

{

_subject = new WeatherData();

}

.... other code....

}

What is a problem with this code?

a couple of.

1. MainWindow should to know about ISubject realization. So, it violate OCP. Class MainWindow do some job and it also instantiate _subject by concrete realization.

2.  If i will want other _subject realization, i will open MainWindow and do changes. It is violates OCP.

3. It is not using Ninject dependency injector ;-)

So, how we fix it?

1. In Visual studio package manager console type :

PM> install-package Ninject

2. Create class, which bind interface and realization by using Ninject:

public class SubjectModule : NinjectModule

{

public override void Load()

{

Bind<ISubject>().To<WeatherData>();

}

}

what is mean, is realization of ISubject is WeatherData

3. Lets create some factory, which use SubjectModule :

public class SubjectFactory

{

public static ISubject Create()

{

IKernel krnl = new StandardKernel(new SubjectModule());

return krnl.Get<ISubject>();

}

}

4. lets do refactoring to MainWindow :

public partial class MainWindow : Window

{

ISubject _subject;

public MainWindow()

{

_subject = SubjectFactory.Create();

}

.... other code....

}

that all!

Now we can change Binding and get other realization inside of MainWindow  without change its code! And, from now, MainWindow  should not know anything about _subject concrete realization

Enjoy

P.S. thanks to Vova about make me to learn it

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