ArrayList.Add Method (System.Collections)

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ArrayList.Add Method
Adds an object to the end of the ArrayList.

Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)

Syntax
Visual Basic (Declaration)
Public Overridable Function Add ( _
	value As Object _
) As Integer
Visual Basic (Usage)
Dim instance As ArrayList
Dim value As Object
Dim returnValue As Integer

returnValue = instance.Add(value)
C#
public virtual int Add (
	Object value
)
C++
public:
virtual int Add (
	Object^ value
)
J#
public int Add (
	Object value
)
JScript
public function Add (
	value : Object
) : int
XAML
Not applicable.

Parameters

value

The Object to be added to the end of the ArrayList. The value can be a null reference (Nothing in Visual Basic).

Return Value

The ArrayList index at which the value has been added.
Exceptions
Exception type Condition

NotSupportedException

The ArrayList is read-only.

-or-

The ArrayList has a fixed size.

Remarks

ArrayList accepts a null reference (Nothing in Visual Basic) as a valid value and allows duplicate elements.

If Count already equals Capacity, the capacity of the ArrayList is increased by automatically reallocating the internal array, and the existing elements are copied to the new array before the new element is added.

If Count is less than Capacity, this method is an O(1) operation. If the capacity needs to be increased to accommodate the new element, this method becomes an O(n) operation, where n is Count.

Example

The following code example shows how to add elements to the ArrayList.

Visual Basic
Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Public Class SamplesArrayList    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("The")
        myAL.Add("quick")
        myAL.Add("brown")
        myAL.Add("fox")
        
        ' Creates and initializes a new Queue.
        Dim myQueue As New Queue()
        myQueue.Enqueue("jumped")
        myQueue.Enqueue("over")
        myQueue.Enqueue("the")
        myQueue.Enqueue("lazy")
        myQueue.Enqueue("dog")
        
        ' Displays the ArrayList and the Queue.
        Console.WriteLine("The ArrayList initially contains the following:")
        PrintValues(myAL, ControlChars.Tab)
        Console.WriteLine("The Queue initially contains the following:")
        PrintValues(myQueue, ControlChars.Tab)
        
        ' Copies the Queue elements to the end of the ArrayList.
        myAL.AddRange(myQueue)
        
        ' Displays the ArrayList.
        Console.WriteLine("The ArrayList now contains the following:")
        PrintValues(myAL, ControlChars.Tab)
    End Sub

    Public Shared Sub PrintValues(myList As IEnumerable, mySeparator As Char)
        Dim obj As [Object]
        For Each obj In  myList
          Console.Write( "{0}{1}", mySeparator, obj )
        Next obj
        Console.WriteLine()
    End Sub 'PrintValues

End Class


' This code produces the following output.
' 
' The ArrayList initially contains the following:
'     The    quick    brown    fox
' The Queue initially contains the following:
'     jumped    over    the    lazy    dog
' The ArrayList now contains the following:
'     The    quick    brown    fox    jumped    over    the    lazy    dog
C#
using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );

      // Creates and initializes a new Queue.
      Queue myQueue = new Queue();
      myQueue.Enqueue( "jumped" );
      myQueue.Enqueue( "over" );
      myQueue.Enqueue( "the" );
      myQueue.Enqueue( "lazy" );
      myQueue.Enqueue( "dog" );

      // Displays the ArrayList and the Queue.
      Console.WriteLine( "The ArrayList initially contains the following:" );
      PrintValues( myAL, '\t' );
      Console.WriteLine( "The Queue initially contains the following:" );
      PrintValues( myQueue, '\t' );

      // Copies the Queue elements to the end of the ArrayList.
      myAL.AddRange( myQueue );

      // Displays the ArrayList.
      Console.WriteLine( "The ArrayList now contains the following:" );
      PrintValues( myAL, '\t' );
   }

   public static void PrintValues( IEnumerable myList, char mySeparator )  {
      foreach ( Object obj in myList )
         Console.Write( "{0}{1}", mySeparator, obj );
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

The ArrayList initially contains the following:
    The    quick    brown    fox
The Queue initially contains the following:
    jumped    over    the    lazy    dog
The ArrayList now contains the following:
    The    quick    brown    fox    jumped    over    the    lazy    dog
*/
C++
using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList, char mySeparator );
int main()
{
   
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   
   // Creates and initializes a new Queue.
   Queue^ myQueue = gcnew Queue;
   myQueue->Enqueue( "jumped" );
   myQueue->Enqueue( "over" );
   myQueue->Enqueue( "the" );
   myQueue->Enqueue( "lazy" );
   myQueue->Enqueue( "dog" );
   
   // Displays the ArrayList and the Queue.
   Console::WriteLine( "The ArrayList initially contains the following:" );
   PrintValues( myAL, '\t' );
   Console::WriteLine( "The Queue initially contains the following:" );
   PrintValues( myQueue, '\t' );
   
   // Copies the Queue elements to the end of the ArrayList.
   myAL->AddRange( myQueue );
   
   // Displays the ArrayList.
   Console::WriteLine( "The ArrayList now contains the following:" );
   PrintValues( myAL, '\t' );
}

void PrintValues( IEnumerable^ myList, char mySeparator )
{
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::Write( "{0}{1}", mySeparator, obj );
   }

   Console::WriteLine();
}

/* 
This code produces the following output.

The ArrayList initially contains the following:
    The    quick    brown    fox
The Queue initially contains the following:
    jumped    over    the    lazy    dog
The ArrayList now contains the following:
    The    quick    brown    fox    jumped    over    the    lazy    dog
*/
J#
import System.*;
import System.Collections.*;

public class SamplesArrayList
{
    public static void main(String[] args)
    {
        // Creates and initializes a new ArrayList.
        ArrayList myAL = new ArrayList();

        myAL.Add("The");
        myAL.Add("quick");
        myAL.Add("brown");
        myAL.Add("fox");

        // Creates and initializes a new Queue.
        Queue myQueue = new Queue();

        myQueue.Enqueue("jumped");
        myQueue.Enqueue("over");
        myQueue.Enqueue("the");
        myQueue.Enqueue("lazy");
        myQueue.Enqueue("dog");

        // Displays the ArrayList and the Queue.
        Console.WriteLine("The ArrayList initially contains the following:");
        PrintValues(myAL, '\t');
        Console.WriteLine("The Queue initially contains the following:");
        PrintValues(myQueue, '\t');

        // Copies the Queue elements to the end of the ArrayList.
        myAL.AddRange(myQueue);

        // Displays the ArrayList.
        Console.WriteLine("The ArrayList now contains the following:");
        PrintValues(myAL, '\t');
    } //main

    public static void PrintValues(IEnumerable myList, char mySeparator)
    {
        IEnumerator objMyEnum = myList.GetEnumerator();
        while (objMyEnum.MoveNext()) {
            Object obj = objMyEnum.get_Current();
            Console.Write("{0}{1}",(Char)mySeparator, obj);
        }
        Console.WriteLine();
    } //PrintValues
} //SamplesArrayList 

/* 
 This code produces the following output.
 
 The ArrayList initially contains the following:
     The    quick    brown    fox
 The Queue initially contains the following:
     jumped    over    the    lazy    dog
 The ArrayList now contains the following:
     The    quick    brown    fox    jumped    over    the    lazy    dog
 */
JScript
import System;
import System.Collections;


// Creates and initializes a new ArrayList.
var myAL : ArrayList = new ArrayList();
myAL.Add( "The" );
myAL.Add( "quick" );
myAL.Add( "brown" );
myAL.Add( "fox" );

// Creates and initializes a new Queue.
var myQueue : Queue  = new Queue();
myQueue.Enqueue( "jumped" );
myQueue.Enqueue( "over" );
myQueue.Enqueue( "the" );
myQueue.Enqueue( "lazy" );
myQueue.Enqueue( "dog" );

// Displays the ArrayList and the Queue.
Console.WriteLine( "The ArrayList initially contains the following:" );
PrintValues( myAL, '\t' );
Console.WriteLine( "The Queue initially contains the following:" );
PrintValues( myQueue, '\t' );

// Copies the Queue elements to the end of the ArrayList.
myAL.AddRange( myQueue );

// Displays the ArrayList.
Console.WriteLine( "The ArrayList now contains the following:" );
PrintValues( myAL, '\t' );

 
function PrintValues( myList : IEnumerable , mySeparator : char  )  {
   var myEnumerator : System.Collections.IEnumerator  = myList.GetEnumerator();
   while ( myEnumerator.MoveNext() )
      Console.Write( "{0}{1}", mySeparator, myEnumerator.Current );
   Console.WriteLine();
}
 /* 
 This code produces the following output.
 
 The ArrayList initially contains the following:
     The    quick    brown    fox
 The Queue initially contains the following:
     jumped    over    the    lazy    dog
 The ArrayList now contains the following:
     The    quick    brown    fox    jumped    over    the    lazy    dog
 */
Platforms

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

Version Information

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0
See Also