C# | Add an object to the end of the ArrayList

ArrayList represents an ordered collection of an object that can be indexed individually. It is basically an alternative to an array. It also allows dynamic memory allocation, adding, searching and sorting items in the list. ArrayList.Add(Object) method adds an object to the end of the ArrayList.

Properties of ArrayList Class:

• Elements can be added or removed from the Array List collection at any point in time.
• The ArrayList is not guaranteed to be sorted.
• The capacity of an ArrayList is the number of elements the ArrayList can hold.
• Elements in this collection can be accessed using an integer index. Indexes in this collection are zero-based.
• It also allows duplicate elements.
• Using multidimensional arrays as elements in an ArrayList collection is not supported.

Syntax:

public virtual int Add (object value);

Here, value is the Object to be added to the end of the ArrayList. The value can be null.

Return Value: This method returns the ArrayList index at which the value has been added.

Exception: This method will give NotSupportedException if the ArrayList is either read-only or fixed size.

Below are the programs to illustrate the use of ArrayList.Add(Object) Method:

Example 1:

// C# code to add an object to
// the end of the ArrayList
using System;
using System.Collections;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating an ArrayList
        ArrayList myList = new ArrayList();

        // Adding elements to ArrayList
        myList.Add("A");
        myList.Add("B");
        myList.Add("C");
        myList.Add("D");
        myList.Add("E");
        myList.Add("F");

        // Displaying the elements in the ArrayList
        foreach(string str in myList)
        {
            Console.WriteLine(str);
        }
    }
}

Output:

A
B
C
D
E
F

Example 2:

// C# code to add an object to
// the end of the ArrayList
using System;
using System.Collections;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating an ArrayList
        ArrayList myList = new ArrayList();

        // Adding elements to ArrayList
        myList.Add(1);
        myList.Add(2);
        myList.Add(3);
        myList.Add(4);
        myList.Add(5);
        myList.Add(6);

        // Displaying the elements in the ArrayList
        foreach(int i in myList)
        {
            Console.WriteLine(i);
        }
    }
}

Output:

1
2
3
4
5
6

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.arraylist.add?view=netframework-4.7.2