Abstract Class vs Interface in .Net

An abstract class in .Net is a class that provides a common base for other classes and can contain both abstract and concrete methods. It cannot be instantiated on its own but can be inherited by other classes.

On the other hand, an interface in .Net is a contract that defines methods and properties that a class must implement. Unlike abstract classes, an interface cannot contain any concrete implementation.

The key difference between an abstract class and an interface in .Net is that a class can inherit only one abstract class while it can implement multiple interfaces.