Abstract Factory Design Pattern

                                                                     Delegates in C#

You want to pass a function as a Parameter ? How does C# handles a callback function or an event handler ? The answer of all these questions is one i.e. a Delegate.

Delegate is a reference type datatype that defines a method prototype. We can define a varibale of delegate just like any other datatype that can refer to any method with the same prototype i,e, signature. 

Define a Delegate => Set a Target Method => Invoke 

eg: public delegate void MyFirstDelegate(string str); // Declaration

Note: declaration can be done outside or even inside the class.

static void MethodA(string str)

{

Console.Writeline(str);

}

//Setting up Target Method

1) MyFirstDelegate del = new MyFirstDelegate(MethodA); 

2) MyFirstDelegate del= MethodA;

3) MyFirstDelegate del = (string msg) => Console.Writeline(msg);

//Invoke 

del.Invoke("Hello World!");

del("Hello World");