What is Indexer ?

Indexer : Indexers allow your class to be used just like an array.

·         Indexer Concept is object act as an array.
Indexer an object to be indexed in the same way as an array.

·         Indexer modifier can be private, public, protected or internal.

·         The return type can be any valid C# types.

·         Indexers in C# must have at least one parameter. Else the compiler will generate a compilation error.

this [Parameter]

{

    get

    {

        // Get codes goes here

    }

    set

    {

        // Set codes goes here

    }

} 

For Example:

using System;

using System.Collections.Generic;

using System.Text;

namespace Indexers

{

    class ParentClass

    {

        private string[] range = new string[5];

        public string this[int indexrange]

        {

            get

            {

                return range[indexrange];

            }

            set

            {

                range[indexrange] = value;

            }

        }

    }

    /* The Above Class just act as array declaration using this pointer */

    class childclass

    {

        public static void Main()

        {

            ParentClass obj = new ParentClass();

            /* The Above Class ParentClass  create one object name is obj */

            obj[0] = "ONE";

            obj[1] = "TWO";

            obj[2] = "THREE";

            obj[3] = "FOUR ";

            obj[4] = "FIVE";

            Console.WriteLine("WELCOME TO C# CORNER HOME PAGE\n");

            Console.WriteLine("\n");

            Console.WriteLine("{0}\n,{1}\n,{2}\n,{3}\n,{4}\n", obj[0], obj[1], obj[2], obj[3], obj[4]);

            Console.WriteLine("\n");

            Console.WriteLine("ALS.Senthur Ganesh Ram Kumar\n");

            Console.WriteLine("\n");

            Console.ReadLine();

        }

    }

}