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CopyTo Method (T[])
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List(Of T).CopyTo Method (T())

Copies the entire List(Of T) to a compatible one-dimensional array, starting at the beginning of the target array.

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

'Declaration
Public Sub CopyTo ( _
	array As T() _
)

Parameters

array
Type: T()

The one-dimensional Array that is the destination of the elements copied from List(Of T). The Array must have zero-based indexing.

ExceptionCondition
ArgumentNullException

array is Nothing.

ArgumentException

The number of elements in the source List(Of T) is greater than the number of elements that the destination array can contain.

This method uses Array.Copy to copy the elements.

The elements are copied to the Array in the same order in which the enumerator iterates through the List(Of T).

This method is an O(n) operation, where n is Count.

The following example demonstrates all three overloads of the CopyTo method. A List(Of T) of strings is created and populated with 5 strings. An empty string array of 15 elements is created, and the CopyTo(T()) method overload is used to copy all the elements of the list to the array beginning at the first element of the array. The CopyTo(T(), Int32) method overload is used to copy all the elements of the list to the array beginning at array index 6 (leaving index 5 empty). Finally, the CopyTo(Int32, T(), Int32, Int32) method overload is used to copy 3 elements from the list, beginning with index 2, to the array beginning at array index 12 (leaving index 11 empty). The contents of the array are then displayed.

Imports System
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Tyrannosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Brachiosaurus")
        dinosaurs.Add("Compsognathus")

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

        ' Declare an array with 15 elements (0 through 14). 
        Dim array(14) As String

        dinosaurs.CopyTo(array)
        dinosaurs.CopyTo(array, 6)
        dinosaurs.CopyTo(2, array, 12, 3)

        Console.WriteLine(vbLf & "Contents of the array:")
        For Each dinosaur As String In array
            Console.WriteLine(dinosaur)
        Next 

    End Sub 
End Class 

' This code example produces the following output: 

'Tyrannosaurus 
'Amargasaurus 
'Mamenchisaurus 
'Brachiosaurus 
'Compsognathus 

'Contents of the array: 
'Tyrannosaurus 
'Amargasaurus 
'Mamenchisaurus 
'Brachiosaurus 
'Compsognathus 

'Tyrannosaurus 
'Amargasaurus 
'Mamenchisaurus 
'Brachiosaurus 
'Compsognathus 

'Mamenchisaurus 
'Brachiosaurus 
'Compsognathus

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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