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This article mainly explains "the definition of C# interface and abstract class". Interested friends may wish to take a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn the definition of C# Interface and Abstract Class.

I. definition

Abstract classes cannot be instantiated. The purpose of an abstract class is to provide a common definition of a base class that can be shared by multiple derived classes. It abstracts the class with or without implementation. Use the keyword abstract

Define it.

As you can see, the abstract class actually inherits the System.Object class, and the compiler generates a default constructor for it.

Interface is the unified naming of a set of method signatures and the definition of a set of behavior specifications, which is defined by the keyword interface.

As you can see, the interface actually treats it as an abstract class, but there is no constructor. Whether an abstract class has a constructor or an interface does not have a constructor, they cannot be instantiated.

II. Differences between members

Abstract class description:

1) an abstract method can be defined, the abstract method has no concrete implementation, it is just a contract of a method, and the method is overridden in a subclass. An abstract class can override the virtual method of the parent class as an abstract method.

2) A non-abstract method can be defined, but it is required to have a concrete implementation, and if the method is a virtual method, it can be overridden in a subclass.

3) Fields, properties, abstract properties, events, and static members can be defined.

IL of abstract method publicabstractintAdd (inta,intb);

The compiler treats the Add method as a virtual method that can be overridden in subclasses.

IL of the virtual method protectedvirtualstringGetAddress (stringaddressID):

It is already a virtual method, so the compiler does not treat it specially.

The IL of method publicvoidAddRoot (Guidid,stringrootName):

It is also a common object method.

API description:

1) you can define properties and indexers, but not fields.

2) events can be defined.

3) the method can be defined, it is only the convention of the method signature, and there is no implementation. The concrete implementation of the method in the implementation class is somewhat similar to the abstract method of the abstract class.

4) Virtual methods cannot be defined.

5) No static members can be defined.

6) API members are fully open by default, and there are no access modifiers.

At this point, I believe you have a deeper understanding of the definition of "C# interface and abstract class". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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