Why does this code produce the output "Base class" and not "Derived2 class"?
namespace TestConsoleApplication { class Baseclass { public void fun() { Console.Write("Base class" + " "); } } class Derived1: Baseclass { new void fun() { Console.Write("Derived1 class" + " "); } } class Derived2: Derived1 { new void fun() { Console.Write("Derived2 class" + " "); } } class Program { public static void Main(string[ ] args) { Derived2 d = new Derived2(); d.fun(); } } } Because you didn't declare the method as public.
You've told it to hide the original definition, rather than override it - which it will do, but the default access modifier is private, not public.
For example, when calling the method from within Derived2:
class Derived2 : Derived1 { new void fun() { Console.Write("Derived2 class" + " "); } public void Test() { fun(); } } class Program { public static void Main(string[] args) { Derived2 d = new Derived2(); d.Test(); //Prints 'Derived2 class' } } Setting it to public will indeed print Derived2 in your original example
public new void fun() { Console.Write("Derived2 class" + " "); } 
public void funis not virtual and not overridden in derived classes.