This document discusses delegates in C#. It defines a delegate as an object that can refer to a method and act as a pointer to a function. Delegates allow methods to be passed as parameters and define callbacks. The delegate declaration specifies a return type and parameter list. A delegate can invoke the method it refers to at runtime rather than compile time. Delegates have uses such as passing methods as arguments and defining multicast delegates that can invoke multiple methods.

1. DELEGATES
This presentation will explain
about delegates in
C#(Csharp).

2.  Delegate is defined as a pointer to a
function.
 A delegate is an object that can refer to a
method.
 Therefore , when you create a delegate
,you are creating an object that can hold
a reference to a method.
 The delegate declaration specifies a
return type and parameter list.

3.  A delegate can invoke the method to which it
refers. Thus, the method that will be invoked
by a delegate is not determined at compile
time , but rather at runtime. This is the
advantage of a delegate.
 You can then initialize the variable as a
reference to any function that has the same
return type and parameter list as that
delegate.
 Delegate is a communication channel, it helps
us to call back after getting the results.

4. The general form of delegate declaration
is shown here:-
Syntax:
public delegate ret-type
delegatename(parameter-list);
• ret-type is the type of value returned by the methods
that the delegate will be calling. The name of the
delegate is specified by name.
• The parameters required by the methods called
through the delegates are specified in the
parameter-list.

5. Uses of delegates:-
• Delegates allow methods to be passed as
parameters.
• Delegates can be used to define call back
methods.
• Delegates are used to pass methods as
arguments to other methods.
• Delegates are like function pointers where
input parameter and return parameter should
be same type.

6. Program:-
using System;
namespace ConsoleApplication1
{
public delegate int myDel(int a, int b)
class Program
{
static void MethodAdd(int a, int b)
{
int c= a+b;
return c;
}
static void Main(string[] args)
{
myDel obj= new myDel(MethodAdd);
int c= obj(10,6)
Console.Writeline(“addition of two no. is: “ +c);
Console.ReadKey();
}
}
}

7. Output:-
addition of two no. is: 16
Types of Delegates:
There are two types of delegate.
1. Single delegate:-
• A delegate is called simple delegate if it
invokes a single method.
• Simple delegate refer to a single method.

8. 2. Multicast delegate:-
• The Multicast delegates can invoke multiple
methods.
• Multicast delegates can send messages to
multiple clients/subscribers
• It uses += sign to broadcast multiple clients.
• It makes two way communication.

9. Program:-
using System;
namespace ConsoleApplication2
{
public delegate int myDel(int a, int b)
class Program
{
static void MethodAdd(int a, int b)
{
Console.Writeline(“The sum is: “ + (a+b));
}
static void MethodMul(int a, int b)
{
Console.Writeline(“The product is: “ + (a*b) );
}
static void Main(string[] args)
{
myDel obj= new myDel(MethodAdd);
obj += new myDel(MethodMul);
Console.ReadKey();
}
}
}