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List(Of T) Constructor (Int32)

Initializes a new instance of the List(Of T) class that is empty and has the specified initial capacity.

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

'Declaration
Public Sub New ( _
	capacity As Integer _
)
'Usage
Dim capacity As Integer 

Dim instance As New List(capacity)

Parameters

capacity
Type: System.Int32

The number of elements that the new list can initially store.

ExceptionCondition
ArgumentOutOfRangeException

capacity is less than 0.

The capacity of a List(Of T) is the number of elements that the List(Of T) can hold. As elements are added to a List(Of T), the capacity is automatically increased as required by reallocating the internal array.

If the size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the List(Of T).

The capacity can be decreased by calling the TrimExcess method or by setting the Capacity property explicitly. Decreasing the capacity reallocates memory and copies all the elements in the List(Of T).

This constructor is an O(n) operation, where n is capacity.

The following code example demonstrates the List(Of T)(Int32) constructor. A List(Of T) of strings with a capacity of 4 is created, because the ultimate size of the list is known to be exactly 4. The list is populated with four strings, and a read-only copy is created by using the AsReadOnly method.

Imports System
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)(4)

        Console.WriteLine(vbLf & "Capacity: {0}", dinosaurs.Capacity)

        dinosaurs.Add("Tyrannosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "Dim roDinosaurs As IList(Of String) = dinosaurs.AsReadOnly")
        Dim roDinosaurs As IList(Of String) = dinosaurs.AsReadOnly

        Console.WriteLine(vbLf & "Elements in the read-only IList:")
        For Each dinosaur As String In roDinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & "dinosaurs(2) = ""Coelophysis""")
        dinosaurs(2) = "Coelophysis"

        Console.WriteLine(vbLf & "Elements in the read-only IList:")
        For Each dinosaur As String In roDinosaurs
            Console.WriteLine(dinosaur)
        Next 

    End Sub 
End Class 

' This code example produces the following output: 

'Capacity: 4 

'Tyrannosaurus 
'Amargasaurus 
'Mamenchisaurus 
'Deinonychus 

'Dim roDinosaurs As IList(Of String) = dinosaurs.AsReadOnly 

'Elements in the read-only IList: 
'Tyrannosaurus 
'Amargasaurus 
'Mamenchisaurus 
'Deinonychus 

'dinosaurs(2) = "Coelophysis" 

'Elements in the read-only IList: 
'Tyrannosaurus 
'Amargasaurus 
'Coelophysis 
'Deinonychus

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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