CODEWITHSUNDEEP
c#design-patternsinterfacemultiple-inheritance
user3159071
user3159071

Reputation:

Multiple Inheritance with Interfaces

I was watching a video (https://www.youtube.com/watch?v=Huj3Jbz-NFw) and here is a picture from it.

enter image description here

My question is: Couldn't class AB be created without using interfaces Such that you hold the A and B objects inside and call them? What information am I throwing away when I say that interface can be ignored.

Upvotes: 0

Views: 191

Answers (3)

Ahuman
Ahuman

Reputation: 762

I think your question is why do we even need an interface.

One of the reasons I could think of is reducing the coupling between the classes. In Test driven development, interfaces help you lot to replace with mock objects.

Check these links for more information. Why do we need interfaces in Java? https://social.msdn.microsoft.com/Forums/vstudio/en-US/8edbf675-6375-4735-997e-bd7bce58f115/why-do-we-need-interfaces?forum=csharpgeneral

Upvotes: 0

Jite
Jite

Reputation: 5847

Yes, the AB class could contain the A and the B objects as class members.
The example in the image is kinda hard to picture in a 'real' example.

I ususaly go after the rule:
If it IS a [type], inherit.
If it HAS a [type], member.

Example.
Cat is an Animal, so Cat inherit from Animal.
Cat has a Tail, so Tail is a member of Cat.

And as C# do not let you inherit from multiple classes, you have to use interfaces.

Cat is an Animal, but it also is a Trickster, and thats two different types.
So it implements the IAnimal and ITrickster interfaces!

Upvotes: 0

Ozan
Ozan

Reputation: 4415

By implementing IA and IB class AB can be used wherever IA or IB are expected:

void doSomethingWithIA(IA item)
{
  item.AMethod();
}

...

AB ab = new AB();
doSomethingWithIA(ab);

If AB had just the same Method names as IA and IB doSomethingWithIA() would not accept it as argument.

Upvotes: 2

Related Questions