List(Of T).Reverse Method (Int32, Int32)

Reverses the order of the elements in the specified range.

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

'Declaration
Public Sub Reverse ( _
	index As Integer, _
	count As Integer _
)

Parameters

index
Type: System.Int32

The zero-based starting index of the range to reverse.

count
Type: System.Int32

The number of elements in the range to reverse.

ExceptionCondition
ArgumentOutOfRangeException

index is less than 0.

-or-

count is less than 0.

ArgumentException

index and count do not denote a valid range of elements in the List(Of T).

This method uses Array.Reverse to reverse the order of the elements.

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

The following example demonstrates both overloads of the Reverse method. The example creates a List(Of T) of strings and adds six strings. The Reverse method overload is used to reverse the list, and then the Reverse(Int32, Int32) method overload is used to reverse the middle of the list, beginning with element 1 and encompassing four elements.

Imports System
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Parasauralophus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Coelophysis")
        dinosaurs.Add("Oviraptor")

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

        dinosaurs.Reverse()

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

        dinosaurs.Reverse(1, 4)

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

    End Sub 
End Class 

' This code example produces the following output: 

'Pachycephalosaurus 
'Parasauralophus 
'Mamenchisaurus 
'Amargasaurus 
'Coelophysis 
'Oviraptor 

'Oviraptor 
'Coelophysis 
'Amargasaurus 
'Mamenchisaurus 
'Parasauralophus 
'Pachycephalosaurus 

'Oviraptor 
'Parasauralophus 
'Mamenchisaurus 
'Amargasaurus 
'Coelophysis 
'Pachycephalosaurus

.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

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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