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ParallelEnumerable::Single<TSource> Method (ParallelQuery<TSource>, Func<TSource, Boolean>)

Returns the only element of a parallel sequence that satisfies a specified condition, and throws an exception if more than one such element exists.

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

[ExtensionAttribute]
public:
generic<typename TSource>
static TSource Single(
	ParallelQuery<TSource>^ source, 
	Func<TSource, bool>^ predicate
)

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.

predicate
Type: System::Func<TSource, Boolean>

A function to test an element for a condition.

Return Value

Type: TSource
The single element of the input sequence that satisfies a condition.

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

AggregateException

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

InvalidOperationException

No element satisfies the condition in predicate. -or- More than one element satisfies the condition in predicate.

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1
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