Queryable.Reverse(Of TSource) Method

Inverts the order of the elements in a sequence.

Namespace:  System.Linq
Assembly:  System.Core (in System.Core.dll)

'Declaration
<ExtensionAttribute> _
Public Shared Function Reverse(Of TSource) ( _
	source As IQueryable(Of TSource) _
) As IQueryable(Of TSource)

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Linq.IQueryable(Of TSource)

A sequence of values to reverse.

Return Value

Type: System.Linq.IQueryable(Of TSource)
An IQueryable(Of T) whose elements correspond to those of the input sequence in reverse order.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable(Of TSource). When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

source is Nothing.

The Reverse(Of TSource)(IQueryable(Of TSource)) method generates a MethodCallExpression that represents calling Reverse(Of TSource)(IQueryable(Of TSource)) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery(Of TElement)(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.

The query behavior that occurs as a result of executing an expression tree that represents calling Reverse(Of TSource)(IQueryable(Of TSource)) depends on the implementation of the type of the source parameter. The expected behavior is that it reverses the order of the elements in source.

The following code example demonstrates how to use Reverse(Of TSource)(IQueryable(Of TSource)) to reverse the order of elements in an array.

        Dim appleLetters As New List(Of Char)(New Char() _
                                              {"a"c, "p"c, "p"c, "l"c, "e"c})

        ' Reverse the order of the characters in the collection. 
        Dim reversed As IQueryable(Of Char) = _
           appleLetters.AsQueryable().Reverse()

        Dim output As New System.Text.StringBuilder
        For Each chr As Char In reversed
            output.Append(chr & " ")
        Next 

        ' Display the output.
        MsgBox(output.ToString())

        ' This code produces the following output: 
        
        ' e l p p a 

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback
Show:
© 2015 Microsoft