#621 – Sealing a Class to Prevent Inheritance

By default, a public class may be inherited from–by a class within the same assembly or even by a class in a different assembly.

To prevent your class from being used as a parent class, you can declare the class with the sealed keyword.  This “seals” the class, so that no one else can inherit from it.

    public sealed class Dog
        public void Bark()
            Console.WriteLine("Dog barking: Woof");

    // Compile-time error: Cannot derive from sealed type DogLibrary.Dog
    public class Terrier : Dog

A sealed class can’t be abstract–since the whole idea of an abstract class is that it is meant to serve as a base class for other classes.


About Sean
Software developer in the Twin Cities area, passionate about software development and sailing.

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