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ParallelEnumerable.DefaultIfEmpty<TSource> Method (ParallelQuery<TSource>, TSource)

.NET Framework (current version)
 
System_CAPS_noteNote

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Returns the elements of the specified parallel sequence or the specified value in a singleton collection if the sequence is empty.

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

public static ParallelQuery<TSource> DefaultIfEmpty<TSource>(
	this ParallelQuery<TSource> source,
	TSource defaultValue
)

Parameters

source
Type: System.Linq.ParallelQuery<TSource>

The sequence to return the specified value for if it is empty.

defaultValue
Type: TSource

The value to return if the sequence is empty.

Return Value

Type: System.Linq.ParallelQuery<TSource>

A sequence that contains defaultValue if source is empty; otherwise, source.

Type Parameters

TSource

The type of the elements of source.

Exception Condition
ArgumentNullException

source 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.

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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