using Intercase and inheritance

[Tony Johansson]

Hello!

Assume I have this IComparable interface and
I implement this IComparable in my class called MyTop see below.
If I now inherit a new class called MySub from MyTop this new class
is not obliged to implement this IComparable interface isn't that strange.

Wouldn't it be more correct to let the inherit class in this case mySub to
be obliged to implement the IComparable
interface.

I'm I totaly wrong here??

I have made a test this MySub just inherit this CompareTo method.

public interface IComparable
{
int CompareTo(IComparable comp);
}
class MyTop : IComparable
{
//Here I implement the CompareTo method
}

class MySub : MyTop
{
....
}

//Tony

[Marc Gravell]

It already *does* implement it - it just uses the implementation
already declared by MyTop.

MySub could choose to re-implement the interface, but that often gets
confusing. A better option is to make the implementation (in MyTop)
virtual so that MySub can override the behaviour. Of course, you may
also wish to consider the impact of IComparable<MySubversus
IComparable<MyTop(using the generic form).

The only way to *force* a subclass to implement something is to leave
a method abstract. But then your base-class must be abstract.

Marc