Indexers in C#

In this article, we are going to learn about the indexers in C#, how to implement indexer in C#?
Submitted by IncludeHelp, on August 11, 2018

An Indexer is a special feature of C# to use an object as an array. If you define an indexer in a class then it will behave like a virtual array. Indexer is also known as smart array in C#. It is not a compulsory or essential part of OOPS.

It is also known as indexed property. It is a class property that allows to access data members using a feature of array.

We use this object to implement indexer in class.

Syntax:

<Modifier> <return type> this[parameter list]
{
	get
	{
		//write code here
	}

	set
	{
		//write code here
	}
}

Example

using System;
using System.Collections;
namespace ConsoleApplication1
{
    
    class Names
    {
        static public int len=10;
        private string []names = new string[len]    ;


        public Names()
        {
            for (int loop = 0; loop < len; loop++)
                names[loop] = "N/A";
        }
        public string this[int ind]
        {
            get
            {
                string str;
                if (ind >= 0 && ind <= len - 1)
                    str = names[ind];
                else
                    str = "...";
                return str;
            }

            set
            {
                if (ind >= 0 && ind <= len - 1)
                    names[ind]=value;
            }
        }
    }

    class Program
    {
        static void Main()
        {
            Names names = new Names();

            names[0] = "Duggu";
            names[1] = "Shaurya";
            names[2] = "Akshit";
            names[3] = "Shivika";
            names[4] = "Veer";

            for (int loop = 0; loop < Names.len; loop++)
            {
                Console.WriteLine(names[loop]);
            }

        }
    }
}

Output

    Duggu
    Shaurya
    Akshit
    Shivika
    Veer
    N/A
    N/A
    N/A
    N/A
    N/A