[In this post you will learn how to extend the methods (extension method) and a nice YouTube video clip explaining the use of Extension Method in C#.]
Introduction
Extension methods are a convenient way to
add methods to classes that you don’t own and so can’t modify directly.
Look at the program given below:
using System;
using System.Collections.Generic;
namespace ConsoleApplication1
{
class Program
{
static void
Main(string[] args)
{
//create the object of the class
Person p =
new Person() { Name =
"Abhimanyu", Age = 22 };
//see the result
Console.WriteLine(p.Name +
", " + p.Age);
Console.ReadKey();
}
}
//class
class Person
{
public string
Name { get; set;
}
public int Age {
get; set; }
}
}
In the above program, I have a ‘Person’
class having two properties ‘Name’ and ‘Age’ and the same I have created an
object of the ‘Person’ class in main method by the name ‘p’ and then assigning
the property value.
Assume I want to extend the ‘Person’ class
(reason may be anything like don’t own class etc.) then what we need to do is to
extend the ‘Person’ class by using a static directive (class or method). Look at
the program snap below.
//extension method
static class
ExtensionMethod
{
public static
string Introduce(this
Person person)
{
return string.Format("Hello {0} ", person.Name);
}
}
In above code the key points are, class or
method should static type and in ‘Introduce’ method parameters we need to write
the name of class (as ‘Person’) which we are extending and its new name (as
‘person’).
Find the complete program here.
using System;
using System.Collections.Generic;
namespace ConsoleApplication1
{
class Program
{
static void
Main(string[] args)
{
//create the object of the class
Person p =
new Person() { Name =
"Abhimanyu", Age = 22 };
//see the result
Console.WriteLine(p.Introduce());
Console.ReadKey();
}
}
//class
class Person
{
public string
Name { get; set;
}
public int Age {
get; set; }
/*
public string Speak()
{
return string.Format("Hello {0} ", Name);
}
*/
}
//extension method
static class
ExtensionMethod
{
public static
string Introduce(this
Person person)
{
return string.Format("Hello {0} ", person.Name);
}
}
}
I hope you will enjoy learning
it. Thanks