Get an enumerator that iterates through the List in C#

In C#, you can get an enumerator that iterates through a List<T> using the GetEnumerator() method. An enumerator provides a way to access each element in a collection sequentially without exposing the underlying structure. The List<T> class implements IEnumerable<T>, which provides enumerator functionality.

Syntax

Following is the syntax to get an enumerator from a List −

List<T>.Enumerator enumerator = list.GetEnumerator();

Following is the syntax to iterate using the enumerator −

while (enumerator.MoveNext()) {
   T currentElement = enumerator.Current;
   // process currentElement
}

How It Works

The enumerator uses two key members −

• MoveNext() − Advances the enumerator to the next element and returns true if successful, false if at the end.

• Current − Gets the element at the current position of the enumerator.

Using GetEnumerator() Method

Example

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main(String[] args) {
      List<String> list1 = new List<String>();
      list1.Add("One");
      list1.Add("Two");
      list1.Add("Three");
      list1.Add("Four");
      list1.Add("Five");
      
      Console.WriteLine("Elements in List1...");
      foreach (string res in list1) {
         Console.WriteLine(res);
      }
      
      List<String> list2 = new List<String>();
      list2.Add("India");
      list2.Add("US");
      list2.Add("UK");
      list2.Add("Canada");
      list2.Add("Poland");
      list2.Add("Netherlands");
      
      Console.WriteLine("Elements in List2...");
      List<String>.Enumerator demoEnum = list2.GetEnumerator();
      while (demoEnum.MoveNext()) {
         string res = demoEnum.Current;
         Console.WriteLine(res);
      }
      
      Console.WriteLine("Is List2 equal to List1? = " + list2.Equals(list1));
   }
}

The output of the above code is −

Elements in List1...
One
Two
Three
Four
Five
Elements in List2...
India
US
UK
Canada
Poland
Netherlands
Is List2 equal to List1? = False

Using Enumerator with Different Data Types

Example

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main(String[] args) {
      List<int> numbers = new List<int>();
      numbers.Add(10);
      numbers.Add(20);
      numbers.Add(30);
      numbers.Add(40);
      numbers.Add(50);
      
      Console.WriteLine("Enumerator iterates through the integer list...");
      List<int>.Enumerator numberEnum = numbers.GetEnumerator();
      while (numberEnum.MoveNext()) {
         int currentNumber = numberEnum.Current;
         Console.WriteLine("Number: " + currentNumber + ", Square: " + (currentNumber * currentNumber));
      }
   }
}

The output of the above code is −

Enumerator iterates through the integer list...
Number: 10, Square: 100
Number: 20, Square: 400
Number: 30, Square: 900
Number: 40, Square: 1600
Number: 50, Square: 2500

Comparison: Enumerator vs foreach

Conclusion

The GetEnumerator()MoveNext() and Current properties. While foreach is simpler for basic iterations, enumerators offer fine-grained control when you need to pause, resume, or conditionally process elements during iteration.