Single(TSource) Method (ParallelQuery(TSource), Func(TSource, Boolean))

Task Parallel System.Threading

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
Assembly:  System.Threading (in System.Threading.dll)

Syntax

Visual Basic (Declaration)
Public Shared Function Single(Of TSource) ( _
	source As ParallelQuery(Of TSource), _
	predicate As Func(Of TSource, Boolean) _
) As TSource
C#
public static TSource Single<TSource>(
	ParallelQuery<TSource> source,
	Func<TSource, bool> predicate
)

Parameters

source
Type: System.Linq..::.ParallelQuery<(Of <(TSource>)>)
The sequence to return the single element of.
predicate
Type: System..::.Func<(Of <(TSource, Boolean>)>)
A function to test an element for a condition.

Type Parameters

TSource
The type of the elements of source.

Return Value

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

Exceptions

ExceptionCondition
System..::.ArgumentNullException source or predicate is a null reference (Nothing in Visual Basic).
System..::.InvalidOperationException No element satisfies the condition in predicate. -or- More than one element satisfies the condition in predicate.
System..::.AggregateException One or more exceptions occurred during the evaluation of the query.
System..::.OperationCanceledException The query was canceled.

See Also