Introduction
Extension methods is a
parametric type It's always used on a static class. The first variable define in
this methods is always "this" keywords. Extension methods are a special kind of
static method, but they are called as if they were instance methods on the
extended type. An extension method is a special kind of static method that
allows you to add new methods to existing types without creating derived types.
Extension Methods you can actually extend the String class to support this
directly. You do it by defining a static class with a set of static methods that
will be your library of extension methods. Extension methods allow existing
classes to be extended without relying on inheritance or having to change the
class source code. This means that if you want to add some methods into the
existing String class you can do it quite easily.
Example
- First add a class in your
application
using
System;
using
System.Collections.Generic;
using
System.Linq;
using
System.Text;
namespace
Ext_method
{
static class
Tom
{
public static
int sum(this
int a, int b)
{
int c = a + b;
return c;
}
public static
int sub(this
int a, int b)
{
int c = a - b;
return c;
}
public static
int mul(this
int a, int b)
{
int c = a * b;
return c;
}
public static
int div(this
int a, int b)
{
int c = a / b;
return c;
}
}
}
- Second write a code on
page lode_event.
Code
using System;
using
System.Collections.Generic;
using
System.ComponentModel;
using
System.Data;
using
System.Drawing;
using
System.Linq;
using
System.Text;
using
System.Windows.Forms;
namespace
Ext_method
{
public partial
class Form1
: Form
{
public Form1()
{
InitializeComponent();
}
int a
= 10, b = 5;
private
void Form1_Load(object
sender, EventArgs e) {
int c = b.sum(a);
int c1 = b.sub(a);
int c2 = b.mul(a);
int c3 = b.div(a);
textBox1.Text = c.ToString();
textBox2.Text = c1.ToString();
textBox3.Text = c2.ToString();
textBox4.Text = c3.ToString();
}
}
}
Output
Summary
It is a simple example of extension methods in this article we have see we know
need to create the object of class. we used the of class on another place help
of parameters but no need to create the object of class.