ParallelEnumerable.OrderByDescending(Of TSource, TKey) Method (ParallelQuery(Of TSource), Func(Of TSource, TKey), IComparer(Of TKey))
.NET Framework (current version)
Sorts the elements of a sequence in descending order by using a specified comparer.
Assembly: System.Core (in System.Core.dll)
<ExtensionAttribute> Public Shared Function OrderByDescending(Of TSource, TKey) ( source As ParallelQuery(Of TSource), keySelector As Func(Of TSource, TKey), comparer As IComparer(Of TKey) ) As OrderedParallelQuery(Of TSource)
Parameters
- source
-
Type:
System.Linq.ParallelQuery(Of TSource)
A sequence of values to order.
- keySelector
-
Type:
System.Func(Of TSource, TKey)
A function to extract a key from an element.
- comparer
-
Type:
System.Collections.Generic.IComparer(Of TKey)
An IComparer{TKey} to compare keys.
Return Value
Type: System.Linq.OrderedParallelQuery(Of TSource)An OrderedParallelQuery{TSource} whose elements are sorted descending according to a key.
Type Parameters
- TSource
The type of elements of source.
- TKey
The type of the key returned by keySelector.
| Exception | Condition |
|---|---|
| ArgumentNullException | source or KeySelector is a null reference (Nothing in Visual Basic).. |
| OperationCanceledException | The query was canceled with the token passed in through WithCancellation. |
| AggregateException | One or more exceptions occurred during the evaluation of the query. |
In contrast to the sequential implementation, this is not a stable sort. See the remarks for OrderBy(Of TSource, TKey) for an approach to implementing a stable sort.
Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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