Insert Element into ArrayList at Specified Index in C#

To insert an element into the ArrayList at the specified index, the code is as follows −

Example

 Live Demo

using System;
using System.Collections;
public class Demo {
   public static void Main() {
      ArrayList list = new ArrayList();
      list.Add("One");
      list.Add("Two");
      list.Add("Three");
      list.Add("Four");
      list.Add("Five");
      list.Add("Six");
      list.Add("Seven");
      list.Add("Eight");  
      Console.WriteLine("ArrayList elements...");
      foreach(string str in list) {
         Console.WriteLine(str);
      }
      Console.WriteLine("ArrayList is read-only? = "+list.IsReadOnly);
      Console.WriteLine("Does the element Six in the ArrayList? = "+list.Contains("Six"));
      list.Insert(4, "Twelve");
      Console.WriteLine("ArrayList elements...UPDATED");
      foreach(string str in list) {
         Console.WriteLine(str);
      }
   }
}

Output

This will produce the following output −

ArrayList elements...
One
Two
Three
Four
Five
Six
Seven
Eight
ArrayList is read-only? = False
Does the element Six in the ArrayList? = True
ArrayList elements...UPDATED
One
Two
Three
Four
Twelve
Five
Six
Seven
Eight

Example

Let us see another example −

 Live Demo

using System;
using System.Collections;
public class Demo {
   public static void Main() {
      ArrayList arrList = new ArrayList();
      arrList.Add(100);
      arrList.Add(200);
      arrList.Add(300);
      arrList.Add(400);
      arrList.Add(500);
      Console.WriteLine("Display elements...");
      IEnumerator demoEnum = arrList.GetEnumerator();
      while (demoEnum.MoveNext()) {
         Object ob = demoEnum.Current;
         Console.WriteLine(ob);
      }
      arrList.Insert(4, 1000);
      Console.WriteLine("Display elements...UPDATED");
      demoEnum = arrList.GetEnumerator();
      while (demoEnum.MoveNext()) {
         Object ob = demoEnum.Current;
         Console.WriteLine(ob);
      }
   }
}

Output

This will produce the following output −

Display elements...
100
200
300
400
500
Display elements...UPDATED
100
200
300
400
1000
500