ParallelEnumerable.OrderByDescending<TSource, TKey> Method (ParallelQuery<TSource>, Func<TSource, TKey>)
Sorts in parallel the elements of a sequence in descending order according to a key.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
public static OrderedParallelQuery<TSource> OrderByDescending<TSource, TKey>( this ParallelQuery<TSource> source, Func<TSource, TKey> keySelector )
Type Parameters
- TSource
The type of elements of source.
- TKey
The type of the key returned by keySelector.
Parameters
- source
- Type: System.Linq.ParallelQuery<TSource>
A sequence of values to order.
- keySelector
- Type: System.Func<TSource, TKey>
A function to extract a key from an element.
Return Value
Type: System.Linq.OrderedParallelQuery<TSource>An OrderedParallelQuery{TSource} whose elements are sorted descending according to a key.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type ParallelQuery<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).| 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 for an approach to implementing a stable sort.
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
