Sealed Classes
Sealed classes are classes that can't be derived from. To prevent other classes from inheriting from a class, make it a sealed class. There are a couple good reasons to create sealed classes, including optimization and security.
Sealing a class avoids the system overhead associated with virtual methods. This allows the compiler to perform certain optimizations that are otherwise unavailable with normal classes.
Another good reason to seal a class is for security. Inheritance, by its very nature, dictates a certain amount of protected access to the internals of a potential base class. Sealing a class does away with the possibility of corruption by derived classes. A good example of a sealed class is the String class. The following example shows how to create a sealed class:
public sealed class CustomerStats
{string gender;decimal income;int numberOfVisits;public CustomerStats()
{
}
}public class CustomerInfo : CustomerStats // error{
}
This example generates a compiler error. Since the CustomerStats class is sealed, it can't be inherited by the CustomerInfo class.The CustomerStats class was meant to be used as an encapsulated object in another class. This is shown by the declaration of a CustomerStats object in the Customer class.
public class Customer
{
CustomerStats myStats; // okay}
By Milan Saxena
Category:
C#,
OOPS
0
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