VB.NET Language in a Nutshell, Second Edition

Name

Array.Copy Method

Class

System.Array

Syntax

Array.Copy(sourceArray, destinationArray, length)

Array.Copy(sourceArray, sourceIndex, destinationArray, _
           destinationIndex, length)

sourceArray (required; any array)

The array to be copied

sourceIndex (required in second overloaded version; integer)

The index in sourceArray at which copying begins

destinationArray (required; any array)

The target array

destinationIndex (required in second overloaded version; Integer)

The index in destinationArray where the first element is to be copied

length (required; Integer)

The number of elements to copy

Return Value

None

Description

Makes a copy of all or part of an array.

Since arrays are reference types, when we set one array variable equal to another, we are just assigning a new reference to the same array. For instance, consider the following code:

Dim a(  ) As Integer = {1, 2, 3}
Dim b(  ) As Integer
' Array assignment
b = a
' Change b
b(0) = 10
' Check a
MsgBox(a(0))    'Displays 10

The fact that changing b(0) also changes a(0) shows that a and b point to the same array.

Rules at a Glance

• Using the first syntax, you can copy a range of values from the beginning of sourceArray to the beginning of destinationArray. Using the second syntax, you can copy a range of values from anywhere in destinationArray to anywhere in targetArray.

• sourceArray and destinationArray must have the same number of dimensions.

• length is the total number of elements to be copied. If sArr1 is a two- dimensional array, for example, ...