How to use the IEnumerable/IEnumerator interfaces

Introduction

IEnumerable is an interface implemented by the System.Collecetion type in .NET that provides the iterator pattern. The definition according to MSDN is:

“Exposes the enumerator, which supports simple iteration over non-generic collections.”

It’s something that you can loop over. That might be a List or Array or anything else that supports a foreach loop. IEnumerator allows you to iterate over List or Array and process each element one by one.

Objective

Explore the usage of IEnumerable and IEnumerator for a user defined class.

Using the code

Let’s first show how both IEnumerable and IEnumerator work: Let’s define a List of strings and iterate each element using the iterator pattern.

// This is a collection that eventually we will use an Enumertor to loop through

// rather than a typical index number if we used a for loop.

List<string> Continents = new List<string>();

Continents.Add("Asia");

Continents.Add("Europe");

Continents.Add("Africa");

Continents.Add("North America");

Continents.Add("South America");

Continents.Add("Australia");

Continents.Add("Antartica");

Now we already knows how to iterate each element using a foreach loop:

// Here is where loop iterate over each item of collection

foreach(string continent in Continents)

{

    Console.WriteLine(continent);

}

Read more: Codeproject

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