Collapse the table of content
Expand the table of content
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here. ArchiveDisclaimer


A sealed class cannot be inherited. It is an error to use a sealed class as a base class. Use the sealed modifier in a class declaration to prevent inheritance of the class.

It is not permitted to use the abstract modifier with a sealed class.

Structs are implicitly sealed; therefore, they cannot be inherited.


// cs_sealed_keyword.cs
// Sealed classes
using System;
sealed class MyClass 
   public int x; 
   public int y;

class MainClass 
   public static void Main() 
      MyClass mC = new MyClass(); 
      mC.x = 110;
      mC.y = 150;
      Console.WriteLine("x = {0}, y = {1}", mC.x, mC.y); 


x = 110, y = 150

In the preceding example, if you attempt to inherit from the sealed class by using a statement like this:

class MyDerivedC: MyClass {}   // Error

you will get the error message:

'MyDerivedC' cannot inherit from sealed class 'MyBaseC'.

See Also

C# Keywords | Modifiers

© 2015 Microsoft