Question

How to create extension method to add method to an existing class in C#

Answer 1

using System;

namespace ConsoleApplication_C_Sharp
{
    static class Program
    {
        static void Main(string[] args)
        {
            int n = 13;

            int r = n.Multiply(10);
            Console.WriteLine(r);

            r = n.Multiply(10).Multiply(3);
            Console.WriteLine(r);
        }

        // extension method
        public static int Multiply(this int n, int mulitiplier)
        {
            return n * mulitiplier;
        }
    }
}


/*
run:
 
130
390
 
*/

 

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Answer 2

using System;

namespace ConsoleApplication_C_Sharp
{
    static class Program
    {
        static void Main(string[] args)
        {
            string s1 = "obi-wan kenobi";
            string s2 = "c# programming language";

            s1.print();
            s2.print();
        }
        // extension method
        public static void print(this string s)
        {
            Console.WriteLine(s);
        }
    }
}


/*
run:
 
Obi-wan kenobi
C# programming language
 
*/

 

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Answer 3

using System;

namespace ConsoleApplication_C_Sharp
{
    static class Program
    {
        static void Main(string[] args)
        {
            int n = 13;

            int r = n.Multiply(10);
            r.Print();

            r = n.Multiply(10).Multiply(3);
            r.Print();

            n.Multiply(10).Print();

        }

        // extension method
        public static int Multiply(this int n, int mulitiplier)
        {
            return n * mulitiplier;
        }
        // extension method
        public static void Print(this int n)
        {
            Console.WriteLine(n);
        }
    }
}


/*
run:
 
130
390
130
 
*/

 

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