what is extention method

Hi Vikas , 

 

public static class StringExtensions
{
    public static string CustomMethod(this string input)
    {
        // Your custom logic here
        return "Modified " + input;
    }
}

// Usage
string result = "Hello".CustomMethod();  // Returns "Modified Hello"
 

An extension method in C# allows you to add new methods to existing classes or interfaces without modifying the original code, providing a way to extend their functionality. These methods appear as if they are part of the original class or interface. They are especially useful when you cannot modify the source code of a class, yet you want to add functionality to it.

public static class StringExtensions
{
    // Extension method to count the number of words in a string
    public static int WordCount(this string str)
    {
        // Split the string by spaces and count the resulting array's length
        string[] words = str.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
        return words.Length;
    }
}

class Program
{
    static void Main()
    {
        string sentence = "This is an example sentence.";

        // Call the extension method on a string object
        int count = sentence.WordCount();

        Console.WriteLine($"The number of words in the sentence is: {count}");
    }
}

An extension method is a special type of static method in C# that allows you to add methods to existing types without modifying the original type.

• The this keyword in front of the first parameter of the extension method indicates that this method is an extension method
• The type of the first parameter specifies the type that you are extending

For Example :

using System;

namespace ExtensionMethods
{
    public static class IntExtension
    {
        public static bool IsEven(this int number)
        {
            return number % 2 == 0;
        }
    }
}

Now you can use the IsEven method on any int object, as if it were an instance method:

int number = 10;
Console.WriteLine(number.IsEven());  // Output: True

int anotherNumber = 11;
Console.WriteLine(anotherNumber.IsEven());  // Output: False

Hello Vikas,

Please refer below link.

https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods

Thanks

Naimish

Hello,

Please refer this thread which will help you out to understand step by step,

https://www.c-sharpcorner.com/article/real-time-example-of-extension-method-in-c-sharp2/

https://youtu.be/Iu7OrL6vCOw

 

Refere above shivprasad koirala sir video on Extension method

Please follow my article on this, for any doubt feel free to ask

https://www.sharpencode.com/article/Linq/an-overview-of-linq/extension-methods