//File: base.cs using System; namespace BaseClassNS { public class MyBaseClass { public void PrintMe() { Console.WriteLine("I am MyBaseClass"); } } } ////////////////////////////////////// //MainClass.cs using System; using BaseClassNS; namespace UsesBaseClass { class DerivedClass : MyBaseClass { } class MainClass { static void Main() { DerivedClass mdc = new DerivedClass(); mdc.PrintMe(); } } }