Inheritance in C#

What is Inheritance?

Inheritance is one of the fundamental concepts of object-oriented programming (OOP) in C#. It allows a class (derived class) to inherit fields and methods from another class (base class). Inheritance promotes code reuse and establishes a relationship between classes.

Why Use Inheritance?

Inheritance allows you to create new classes that reuse, extend, and modify the behavior of existing classes. It provides a clear structure and reduces code duplication.

Example: Inheritance in C#

Here’s an example where a Vehicle class is the base class, and Car is the derived class inheriting from Vehicle.

Example Code:

public class Vehicle
{
    public string Make { get; set; }
    public int Year { get; set; }

    public void DisplayInfo()
    {
        Console.WriteLine($"Make: {Make}, Year: {Year}");
    }
}

public class Car : Vehicle
{
    public int NumberOfDoors { get; set; }

    public void DisplayCarInfo()
    {
        Console.WriteLine($"Make: {Make}, Year: {Year}, Doors: {NumberOfDoors}");
    }
}

// Usage
Car car = new Car();
car.Make = "Toyota";
car.Year = 2022;
car.NumberOfDoors = 4;
car.DisplayCarInfo();  // Output: Make: Toyota, Year: 2022, Doors: 4
        

In this example, the Car class inherits the properties and methods from the Vehicle class and adds additional functionality with the NumberOfDoors property and DisplayCarInfo method.

Types of Inheritance

• Single Inheritance: A derived class inherits from a single base class.
• Multilevel Inheritance: A class is derived from a class that is also derived from another class.
• Hierarchical Inheritance: Multiple derived classes inherit from a single base class.

The base Keyword

The base keyword is used to access members of the base class from within a derived class. It can be used to call base class constructors, methods, or properties.

Example of Using base Keyword:

public class Vehicle
{
    public string Make { get; set; }

    public Vehicle(string make)
    {
        Make = make;
    }

    public void DisplayInfo()
    {
        Console.WriteLine($"Vehicle Make: {Make}");
    }
}

public class Car : Vehicle
{
    public Car(string make) : base(make) // Using 'base' to call the base class constructor
    {
    }
}

// Usage
Car car = new Car("Honda");
car.DisplayInfo();  // Output: Vehicle Make: Honda
        

In this example, the base keyword is used to call the base class constructor from the derived class constructor.

Key Points to Remember

• Inheritance enables code reuse by allowing derived classes to inherit fields and methods from base classes.
• The base keyword is used to access members of the base class.
• Inheritance promotes hierarchical relationships between classes, creating a clear class structure.
• In C#, multiple inheritance is not supported directly, but interfaces can be used to achieve similar results.