In this C# presentation will discuss about a concept called Delegates.

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();
}
}
}