List(Of T).CopyTo Method (Int32, T(), Int32, Int32)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Copies a range of elements from the List(Of T) to a compatible one-dimensional array, starting at the specified index of the target array.
Assembly: mscorlib (in mscorlib.dll)
'Declaration Public Sub CopyTo ( _ index As Integer, _ array As T(), _ arrayIndex As Integer, _ count As Integer _ )
Parameters
- index
- Type: System.Int32
The zero-based index in the source List(Of T) at which copying begins.
- 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.
- arrayIndex
- Type: System.Int32
The zero-based index in array at which copying begins.
- count
- Type: System.Int32
The number of elements to copy.
| Exception | Condition |
|---|---|
| ArgumentNullException | array is Nothing. |
| ArgumentOutOfRangeException | index is less than 0. -or- arrayIndex is less than 0. -or- count is less than 0. |
| ArgumentException | The number of elements from index to the end of the source List(Of T) is greater than the available space from arrayIndex to the end of the destination array. |
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 code 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.Collections.Generic Public Class Example Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock) Dim dinosaurs As New List(Of String) dinosaurs.Add("Tyrannosaurus") dinosaurs.Add("Amargasaurus") dinosaurs.Add("Mamenchisaurus") dinosaurs.Add("Brachiosaurus") dinosaurs.Add("Compsognathus") outputBlock.Text &= vbCrLf For Each dinosaur As String In dinosaurs outputBlock.Text &= dinosaur & vbCrLf 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) outputBlock.Text &= vbLf & "Contents of the array:" & vbCrLf For Each dinosaur As String In array outputBlock.Text &= dinosaur & vbCrLf 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