Interfaces can inherit from other interfaces.
For instance:
interface Printable{ void Print(); } interface Formattable : Printable { void Format(); }
Formattable "inherits" all the members of Printable.
Types that implement Formattable must also implement the members of Printable.
The following code shows how to extend interface.
using System; interface Interface1 { void ShowInterface1(); } interface Interface2 { void ShowInterface2(); } //Interface implementing multiple inheritance interface Interface3 : Interface1, Interface2 { void ShowInterface3(); } class MyClass : Interface3 { public void ShowInterface1() {/*from w w w. j a va 2 s .c om*/ Console.WriteLine("ShowInterface1() is completed."); } public void ShowInterface2() { Console.WriteLine("ShowInterface2() is completed."); } public void ShowInterface3() { Console.WriteLine("ShowInterface3() is completed."); } } class Program { static void Main(string[] args) { MyClass myClassOb = new MyClass(); Interface1 ob5A = myClassOb; ob5A.ShowInterface1(); Interface2 ob5B = myClassOb; ob5B.ShowInterface2(); Interface3 ob5C = myClassOb; ob5C.ShowInterface3(); } }