Inheritance & base

Syntax

class Child : Parent {\n  public Child() : base() { }\n}

Examples

public class Animal
{
    public string Name;

    public Animal(string name)
    {
        Name = name;
    }

    public void Speak()
    {
        Console.WriteLine($"{Name} makes a sound");
    }
}

public class Dog : Animal
{
    public Dog(string name) : base(name)  // call the base constructor
    {
    }
}

Dog rex = new Dog("Rex");
rex.Speak();  // Rex makes a sound (inherited method)

public class Animal
{
    public string Name;
    public Animal(string name) { Name = name; }
}

public class Cat : Animal
{
    public bool IsIndoor;

    public Cat(string name, bool indoor) : base(name)
    {
        IsIndoor = indoor;
    }
}

Cat whiskers = new Cat("Whiskers", true);
Console.WriteLine($"{whiskers.Name}, indoor: {whiskers.IsIndoor}");

public class Animal
{
    public virtual void Speak()
    {
        Console.WriteLine("Some generic animal sound");
    }
}

public class Dog : Animal
{
    public override void Speak()
    {
        Console.WriteLine("Woof!");
    }
}

Animal a = new Dog();
a.Speak();  // Woof! - the overridden version runs

public class Employee
{
    public virtual void Work()
    {
        Console.WriteLine("Doing general work tasks");
    }
}

public class Manager : Employee
{
    public override void Work()
    {
        base.Work();  // still do the general work first
        Console.WriteLine("Also managing the team");
    }
}

Manager m = new Manager();
m.Work();
// Doing general work tasks
// Also managing the team

Best practices

• Use : base(...) in a derived class constructor to reuse the parent's setup logic instead of duplicating it
• Mark a base class method virtual only when you actually intend subclasses to override it - not every method needs to be overridable
• Use base.Method() inside an override when you want to extend the parent behavior rather than fully replace it
• Favor composition (a class containing an instance of another) over deep inheritance chains when the relationship is not truly "is-a"

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation