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ParallelEnumerable.SingleOrDefault<TSource> Method (ParallelQuery<TSource>)

Returns the only element of a parallel sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

Namespace:  System.Linq
Assemblies:   System.Linq.Parallel (in System.Linq.Parallel.dll)
  System.Core (in System.Core.dll)

public static TSource SingleOrDefault<TSource>(
	this ParallelQuery<TSource> source
)

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Linq.ParallelQuery<TSource>

The sequence to return the single element of.

Return Value

Type: TSource
The single element of the input sequence, or default() if the sequence contains no elements.

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).

ExceptionCondition
OperationCanceledException

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

ArgumentNullException

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

AggregateException

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

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

.NET for Windows Phone apps

Supported in: Windows Phone 8.1

Portable Class Library

Supported in: Portable Class Library
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