CODEWITHSUNDEEP
c#.netvisual-studiooop
Alex Gordon
Alex Gordon

Reputation: 60691

hiding implementation details through the usage of protected virtual

A coworker introduced me to the concept of hiding implementation details through allowing the derived class to override the private field initializations.

For example I have a base class:

public class Animal
{
   private Dog dog;
   private Cat cat;
   private Mouse mouse;

   protected virtual void Init()
   {
      dog = new Dog();
      cat = new Cat();
      mouse = new Mouse();
   }

   public void DoStuff() {}

}

This allows me to override the initialization within a derived class of the base class privates:

public class Cookie : Animal
{
   protected override void init()
   {
      //do whatever i want here
   }
}
  1. Does this type of implementation-detail-hiding have a name?
  2. Would I ever call Init() from Animal or does this pattern insist on Init() because called from a derived class?

What am I trying to achieve?

I have a class (animal in the example above) that has about 20 private objects that need to be initialized, and I want to be able to define my own way of initializing them specifically when doing unit testing.

Upvotes: 0

Views: 415

Answers (2)

sm_
sm_

Reputation: 2602

1) This is simply overriding, i am not aware that it is more than that. But you cannot access private fields in a subclass, they have to be protected as well so you can access them in your subclass.

2) Your question is not clear, but i am guessing you are asking how you can call the method of the base class from within the override. all you need to do is 

public class Cookie : Animal
{
   protected override void init()
   {
      //do whatever you want here
      base.init(); //This line will call the init() function in Animal. 
      //do whatever you want here
   }
}

Upvotes: 2

Jan Paolo Go
Jan Paolo Go

Reputation: 6522

That is simply called override.

An override method provides a new implementation of a member that is inherited from a base class.

You can invoke the base class' overriden method Init() from the derived class by using base.Init();.

Upvotes: 1

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