C# Inheritance - Subclasses and Base Classes

C# Inheritance (Subclass and Superclass)

In C#, it is possible to inherit fields and methods from one class to another. We group the "inheritance concept" into two categories:

Derived Class (child) - the class that inherits from another class
Base Class (parent) - the class being inherited from

To inherit from a class, use the : symbol.

In the example below, the Car class (child) inherits the fields and methods from the Vehicle class (parent):

Examples

Inheritance Example

Car inherits brand and honk from Vehicle.

using System;

class Vehicle  // Base class (parent) 
{
  public string brand = "Ford";  // Vehicle field
  public void honk()             // Vehicle method 
  {                    
    Console.WriteLine("Tuut, tuut!");
  }
}

class Car : Vehicle  // Derived class (child)
{
  public string modelName = "Mustang";  // Car field
}

class Program
{
  static void Main(string[] args)
  {
    Car myCar = new Car();
    myCar.honk();
    Console.WriteLine(myCar.brand + " " + myCar.modelName);
  }
}

Sealed Keyword

Preventing inheritance.

using System;

sealed class Vehicle 
{
   public void honk() { Console.WriteLine("Tuut"); }
}

// class Car : Vehicle { } // Error: cannot inherit from sealed class

class Program
{
    static void Main()
    {
        Vehicle v = new Vehicle();
        v.honk();
    }
}