C# ArrayList

The ArrayList class is part of the System.Collections namespace and provides a dynamic array that can grow or shrink in size during runtime.

 

It is considered one of the older collections in C# and has been largely superseded by the generic collections introduced in .NET Framework 2.0, such as List<T>.

 

Example of a ArrayList in C#.

using System;
using System.Collections;

class Program
{
    static void Main()
    {
        // Creating an ArrayList
        ArrayList arrayList = new ArrayList();

        // Adding elements to the ArrayList
        arrayList.Add(10);
        arrayList.Add("Hello");
        arrayList.Add(3.14);

        // Accessing elements in the ArrayList
        Console.WriteLine("Elements in the ArrayList:");
        foreach (var item in arrayList)
        {
            Console.WriteLine(item);
        }

        // Removing an element from the ArrayList
        arrayList.Remove("Hello");

        Console.WriteLine("\nAfter removing 'Hello':");
        foreach (var item in arrayList)
        {
            Console.WriteLine(item);
        }
    }
}

 

ArrayList stores objects, so elements of different types can be added.

 

However, this flexibility comes with a trade-off: you lose type safety, and you may need to perform explicit type casting when retrieving elements.

 

It's generally recommended to use the generic collections like List<T> instead of ArrayList when working with collections in modern C# code, as they provide type safety and improved performance.