abstract class question

[Victor Fees]

If I take an abstract class, as shown:

public abstract class PMData
{
public abstract void Save();
}


and then create an inherited class, such as:

public class Property : PMData
{

public override void Save()
{
return;
}
}


In other code, when I instantiate Property, the intellisense in Visual
Studio 2003 allows me to choose between PMData.Save() and Property.Save().
Choosing one or the other doesn't appear to affect the result of the code .
.. . but for some reason, I just didn't think that PMData.Save() would
really be an option when I instantiate Property.

Anyone have any input on this?

-Victor

 

[mia lanui]

I don't understand why intellisense does that either.

Polymorphism determines which class's implementation gets called at runtime.

 

[Jeff Louie]

Victor... It does not matter if you call the base class method or the
subclass method, the "proper" method will be called at runtime due to
polymorphism. More explanation at:

http://www.geocities.com/jeff_louie/OOP/oop4.htm

abstract class Drawable
{
    public abstract String DrawYourself();
}
class Circle : Drawable
{
    public override String DrawYourself()
    {
        return "Circle";
    }
}
class Square : Drawable
{
    public override String DrawYourself()
    {
        return "Square";
    }
}

http://www.geocities.com/jeff_louie/OOP/oop9.htm

// an interface version of Drawable
interface IDrawable
{
void DrawYourself();
}
class Circle : IDrawable
{
public void DrawYourself()
{
System.Console.WriteLine("Circle");
}
}

class Square : IDrawable
{
public void DrawYourself()
{
System.Console.WriteLine("Square");
}
}


Regards,
Jeff

In other code, when I instantiate Property, the intellisense in Visual

Studio 2003 allows me to choose between PMData.Save() and
Property.Save().<