using System; // Define a custom delegate that has a string parameter and returns void. delegate void CustomDel(string s); class TestClass { // Define two methods that have the same signature as CustomDel. static void Hello(string s) { System.Console.WriteLine(" Hello, {0}!", s); } static void Goodbye(string s) { System.Console.WriteLine(" Goodbye, {0}!", s); } static void Main() { // Declare instances of the custom delegate. CustomDel hiDel, byeDel, multiDel, multiMinusHiDel; // In this example, you can omit the custom delegate if you // want to and use Actioninstead. //Action hiDel, byeDel, multiDel, multiMinusHiDel; // Create the delegate object hiDel that references the // method Hello. hiDel = Hello; // Create the delegate object byeDel that references the // method Goodbye. byeDel = Goodbye; // The two delegates, hiDel and byeDel, are combined to // form multiDel. multiDel = hiDel + byeDel; // Remove hiDel from the multicast delegate, leaving byeDel, // which calls only the method Goodbye. multiMinusHiDel = multiDel - hiDel; Console.WriteLine("Invoking delegate hiDel:"); hiDel("A"); Console.WriteLine("Invoking delegate byeDel:"); byeDel("B"); Console.WriteLine("Invoking delegate multiDel:"); multiDel("C"); Console.WriteLine("Invoking delegate multiMinusHiDel:"); multiMinusHiDel("D"); } } /* Output: Invoking delegate hiDel: Hello, A! Invoking delegate byeDel: Goodbye, B! Invoking delegate multiDel: Hello, C! Goodbye, C! Invoking delegate multiMinusHiDel: Goodbye, D! */