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ArraySegment Generic Structure

Note: This structure is new in the .NET Framework version 2.0.

Delimits a section of a one-dimensional array.

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

'Declaration
<SerializableAttribute> _
Public Structure ArraySegment(Of T)
'Usage
Dim instance As ArraySegment(Of T)

J# supports the use of generic types and methods, but not the declaration of new ones.
JScript does not support generic types and methods.

Type Parameters

T

The type of the elements in the array segment.

ArraySegment is a wrapper around an array that delimits a range of elements in that array. Multiple ArraySegment instances can refer to the same original array and can overlap.

The Array property returns the entire original array, not a copy of the array; therefore, changes made to the array returned by the Array property are made to the original array.

The original array must be one-dimensional and must have zero-based indexing.

The following code example passes an ArraySegment structure to a method.

Imports System

Public Class SamplesArray

    Public Shared Sub Main()

        ' Create and initialize a new string array.
        Dim myArr As String() =  {"The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"}

        ' Display the initial contents of the array.
        Console.WriteLine("The original array initially contains:")
        PrintIndexAndValues(myArr)

        ' Define an array segment that contains the entire array.
        Dim myArrSegAll As New ArraySegment(Of String)(myArr)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The first array segment (with all the array's elements) contains:")
        PrintIndexAndValues(myArrSegAll)

        ' Define an array segment that contains the middle five values of the array.
        Dim myArrSegMid As New ArraySegment(Of String)(myArr, 2, 5)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The second array segment (with the middle five elements) contains:")
        PrintIndexAndValues(myArrSegMid)

        ' Modify the fourth element of the first array segment myArrSegAll.
        myArrSegAll.Array(3) = "LION"

        ' Display the contents of the second array segment myArrSegMid.
        ' Note that the value of its second element also changed.
        Console.WriteLine("After the first array segment is modified, the second array segment now contains:")
        PrintIndexAndValues(myArrSegMid)

    End Sub 'Main

    Public Shared Sub PrintIndexAndValues(arrSeg As ArraySegment(Of String))
        Dim i As Integer
        For i = arrSeg.Offset To (arrSeg.Offset + arrSeg.Count - 1)
            Console.WriteLine("   [{0}] : {1}", i, arrSeg.Array(i))
        Next i
        Console.WriteLine()
    End Sub 'PrintIndexAndValues 

    Public Shared Sub PrintIndexAndValues(myArr as String())
        Dim i As Integer
        For i = 0 To (myArr.Length - 1)
            Console.WriteLine("   [{0}] : {1}", i, myArr(i))
        Next i
        Console.WriteLine()
    End Sub 'PrintIndexAndValues 

End Class 'SamplesArray


'This code produces the following output.
'
'The original array initially contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The first array segment (with all the array's elements) contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The second array segment (with the middle five elements) contains:
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'
'After the first array segment is modified, the second array segment now contains:
'   [2] : brown
'   [3] : LION
'   [4] : jumps
'   [5] : over
'   [6] : the


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 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 .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

.NET Compact Framework

Supported in: 2.0

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