Comments by FTWO (Top 9 by date)

It may lead to far. That's funny.

I wanted to see if I was being clear in the question I was asking
ie why would you instantiate like this (using base class reference in derived class:
BaseClass objBaseClass= new DervivedClass()
and not like this
ClassDerived objDerivedClass = new Derived()
If objBaseClass.Show() and objDerivedClass.Show() would always run derived method.
In any case Sagar cleared things up somewhat for me.

Incidentally can you recommend good OOP literature, I have been reading about dynamic dispatch and virtual method tables but mainly from forums or Wikipedia, clearly I need a good recommendation.

Ah Yes - thank you Sagar, I think that clears it up


1. Without overwrite in DerivedClass show() method

if instantiated like this (using base class reference in derived class
BaseClass objBaseClass= new DervivedClass()

The base class method will be run for command objBaseClass.Show()

if instantiated like this
DerivedClass objBaseClass= new DervivedClass()

The derived class method will be run for command objBaseClass.Show()

2. With overwrite in DerivedClass show() method
The derived class method will run regardless

just so there's no confusion can you tell me what you think I am asking

It's a beginners question I suppose. "The use" is to help me understand it.
It's not code that is being used anywhere, it's an example I'm giving so I can understand the principles.
I saw the code here http://www.codeproject.com/Articles/602141/Polymorphism-in-NET
and was surprised that the class was being instantiated as
ClassBase ObjectBase = new Derived() ---I'm calling this case 1
and not
ClassDerived ObjectDerived = new Derived() -- I'm calling this case 2

So I'm asking the question why, so that I can learn from the answer - maybe that's the use.