This article is about C# Simple tutorial for beginners , This is the first 11 piece . Thank you for watching. , Remember to follow me , There are more tutorial articles to follow , thank you .
The environment of this paper is Visual Studio 2019.
One 、 What is inheritance
Inheritance is a basic feature of object-oriented programming . By means of inheritance , Be able to define reusability （ Inherit ）、 A subclass that extends or modifies the behavior of a parent class . A class whose members are inherited is called a base class . A class that inherits members of a base class is called a derived class .
such as , The breast length Ru skirt is a kind of Han clothing , A model family is a kind of family , Tilapia 、 Perch is a kind of fish .
that ： The shape of Hanfu 、 family 、 fish , It's the base class , It's also called the parent . Ruskirt with chest together 、 Model family 、 Tilapia and perch , Is a derived class , Also called subclass .
Two 、C# The way to write inheritance in
Pictured above , The inheritance syntax is to use an English half colon （:） To define .
3、 ... and 、C# The main point of inheritance in
1、 stay C# in , Inherit , It's single inheritance , It means every subclass , There can be at most one parent class .
2、 stay C# in , Inheritance is hierarchical , It can be inherited from generation to generation , It's kind of like the protoss genealogy .
Pictured above , The father of perch is fish , The father of fish is animal , The father of an animal is a creature , There are layers of inheritance .
3、 stay C# in , All classes , They are all implicitly inherited from Object Base class . Because of that , therefore , What you see above “ fish ” class , It's empty inside, nothing , But if you output , You'll find something else , These things are actually made of Object Base class . As shown in the figure below ：
Red circle of definition , It's an implicit base class Object Defined .
Four 、 abstract class
Once you inherit a class , Then this class is called the base class （ Parent class ） 了 .
If you expect the base class not to be instantiated （ namely new An object ）, Then you can add abstract keyword .
5、 ... and 、 Sealing class
If you expect a class , It's not allowed to be inherited , Then you can add sealed keyword , It means sealing .
Pictured above , Once in sealed keyword , Derivation will be prohibited .
Have a good meal .