Understanding C# Inheritance, Polymorphism and Method Overriding: A Beginner's Guide with Examples

C# is an object-oriented programming language that supports inheritance. Inheritance is a mechanism by which a new class can be derived from an existing class. The existing class is called the base class or parent class, and the new class is called the derived class or child class. Inheritance allows the derived class to inherit the properties and behavior of the base class, and it can also add its own properties and behavior. 

In this article, we will explore the concept of inheritance in C# in detail. We will cover the following topics: 

  1. Base Class and Derived Class 
  2. Types of Inheritance 
  3. Polymorphism 
  4. Method Overriding 

Base Class and Derived Class: 
A base class is the class from which other classes can be derived. It is also known as a parent class or superclass. A derived class is a class that is derived from the base class. It is also known as a child class or subclass. The derived class inherits all the members of the base class, including fields, methods, and properties. 

To define a derived class in C#, you use the following syntax: 
class DerivedClass : BaseClass
{
    // fields, methods, and properties
}

The colon (:) is used to specify the base class. 

Types of Inheritance: 
In C#, there are five types of inheritance: Single inheritance: 
  1. A derived class can inherit from only one base class. 
  2. Multilevel inheritance: A derived class can inherit from a base class, which in turn can inherit from another base class. 
  3. Hierarchical inheritance: Multiple classes can inherit from the same base class. 
  4. Multiple inheritance: A derived class can inherit from multiple base classes. However, C# does not support multiple inheritance. 
  5. Hybrid inheritance: A combination of two or more types of inheritance. 

Polymorphism: 
Polymorphism is the ability of an object to take on multiple forms. In C#, polymorphism is achieved through inheritance. Polymorphism allows you to write code that can work with objects of different classes that have a common base class. For example, you can have a method that takes an object of the base class as a parameter, and then you can pass objects of any derived class to that method. 

Method Overriding: 
Method overriding is a feature of inheritance that allows a derived class to provide a specific implementation of a method that is already defined in the base class. To override a method, you must use the virtual keyword when defining the method in the base class, and use the override keyword when defining the method in the derived class. 

Inheritance is an important concept in object-oriented programming, and C# provides support for inheritance through classes. In this article, we have explored the concept of inheritance in C# in detail. We have covered the base class and derived class, types of inheritance, polymorphism, and method overriding. With this knowledge, you can implement inheritance in your code and create more robust and scalable applications.