Explain Delegates and different type of delegates in C#
Define Delegate
A delegate in C# is similar to a function pointer in C or C++. It allows the programmer to encapsulate a reference to a method (nothing but an event) inside a delegate object.
Microsoft C# Delegates have the following properties:
· Delegates are similar to C++ function pointers, but are type safe.
· Delegates allow methods to be passed as parameters.
· Delegates can be used to define callback methods.
· Delegates can be chained together; for example, multiple methods can be called on a single event.
Declarations:
Syntax:
<Access modifiers> delegate <datatype> delegatename() // here delegate is keyword.
Example:
public delegatedouble Delegate_Prod();
Delegate Types: Delegates are two types basically.
1. Single cast delegates:- Single cast delegates refers one method at a time
2. Multicast delegates:- Multicast delegates refers more than one method.
Single Cast Delegate:
using System;
namespace Test.BasicDelegate
{
public delegate void SingleCastDelegate(); //Delegate definition
class TestDelegate
{
public static void MyFunc()
{
Console.WriteLine(“Hi, I was called by Delegate...“);
Console.WriteLine(“*************************“);
}
public static void Main(string[] args)
{
SingleCastDelegate ObjSC = new SingleCastDelegate (MyFunc); //Creating the Delegate Instance
SingleCastDelegate(); //invoking the MyFunc method
Console.ReadLine();
}
}
}
OUTPUT:
Hi, I was called by Delegate...
*************************
MultiCast Delegate:
delegate void MulticastDelegate(int x, int y);
Class Class2
{
static void Method1(int x, int y)
{
Console.WriteLine("Hi, u r in Method 1");
}
static void Method2(int x, int y)
{
Console.WriteLine("Hi, u r in Method 2");
}
public static void <place w:st="on" />Main</place />()
{
MulticastDelegate objfunc = new MulticastDelegate(Method1);
objfunc += new MulticastDelegate (Method2);
objfunc (10,20); // Method1 and Method2 are called
objfunc -= new MulticastDelegate(Method1);
objfunc(40,50); // Only Method2 is called
}
}
OUTPUT:
Hi, u r in Method 1
Hi, u r in Method 2
Hi, u r in Method 2
Conclusion: This article would help to understand Microsoft delegates in C# using simple examples. And these delegates are especially developed by Microsoft is to create events and to change some objects ability to customize their behavior.
