Inheritance in dotnet framework

Inheritance is an object-oriented concept that lets a derived class reuse (inherit) the fields, properties, and methods of a base class, promoting code reusability and a clear class hierarchy. In .NET you get:

• Single inheritance: Each class can inherit from one direct base class.
• Polymorphism: Base-class references can invoke derived-class implementations (via virtual/override).

Code Example

using System;
 
namespace InheritanceDemo
{
    // Base class
    public class Animal
    {
        public string Name { get; set; }
 
        // Virtual method allows overriding in derived classes
        public virtual void Speak()
        {
            Console.WriteLine($"{Name} makes a sound.");
        }
    }
 
    // Derived class
    public class Dog : Animal
    {
        // Override the virtual method
        public override void Speak()
        {
            Console.WriteLine($"{Name} says: Woof!");
        }
 
        // New method specific to Dog
        public void Fetch()
        {
            Console.WriteLine($"{Name} is fetching the ball!");
        }
    }
 
    class Program
    {
        static void Main(string[] args)
        {
            // Instantiate derived class
            Dog myDog = new Dog { Name = "Buddy" };
            // Calls overridden method
            myDog.Speak();    // Output: Buddy says: Woof!
            // Calls method defined only in Dog
            myDog.Fetch();    // Output: Buddy is fetching the ball!
 
            // Polymorphism: base-class reference to a derived instance
            Animal pet = new Dog { Name = "Charlie" };
            pet.Speak();      // Output: Charlie says: Woof!
        }
    }
}

• virtual on the base-class method marks it as overridable.
• override in the derived class provides a new implementation.
• You can also add new members (like Fetch()) that are specific to the derived class.