ParallelEnumerable::GroupBy<TSource, TKey> Method (ParallelQuery<TSource>^, Func<TSource, TKey>^, IEqualityComparer<TKey>^)

.NET Framework (current version)
 

Groups in parallel the elements of a sequence according to a specified key selector function and compares the keys by using a specified IComparer<T>.

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

public:
generic<typename TSource, typename TKey>
[ExtensionAttribute]
static ParallelQuery<IGrouping<TKey, TSource>^>^ GroupBy(
	ParallelQuery<TSource>^ source,
	Func<TSource, TKey>^ keySelector,
	IEqualityComparer<TKey>^ comparer
)

Parameters

source
Type: System.Linq::ParallelQuery<TSource>^

An OrderedParallelQuery<TSource> that contains elements to sort.

keySelector
Type: System::Func<TSource, TKey>^

A function to extract a key from an element.

comparer
Type: System.Collections.Generic::IEqualityComparer<TKey>^

An IComparer<T> to compare keys.

Return Value

Type: System.Linq::ParallelQuery<IGrouping<TKey, TSource>^>^

A sequence of groups that are sorted descending according to TKey.

Type Parameters

TSource

The type of elements of source.

TKey

The type of the key returned by keySelector>.

Exception Condition
OperationCanceledException

The query was canceled with the token passed in through WithCancellation.

ArgumentNullException

source or action is a null reference (Nothing in Visual Basic).

AggregateException

One or more exceptions occurred during the evaluation of the query.

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
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