ParallelEnumerable.SingleOrDefault Method

Definition

Namespace:

System.Linq

Assembly:

System.Linq.Parallel.dll

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.

Overloads

SingleOrDefault<TSource>(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.
SingleOrDefault<TSource>(ParallelQuery<TSource>, Func<TSource,Boolean>)	Returns the only element of a parallel sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.

SingleOrDefault<TSource>(ParallelQuery<TSource>)

Source:

ParallelEnumerable.cs

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.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource SingleOrDefault(System::Linq::ParallelQuery<TSource> ^ source);

public static TSource? SingleOrDefault<TSource> (this System.Linq.ParallelQuery<TSource> source);

static member SingleOrDefault : System.Linq.ParallelQuery<'Source> -> 'Source

<Extension()>
Public Function SingleOrDefault(Of TSource) (source As ParallelQuery(Of TSource)) As TSource

Type Parameters

TSource

The type of the elements of source.

Parameters

source

ParallelQuery<TSource>

The sequence to return the single element of.

Returns

TSource

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

Exceptions

OperationCanceledException

The query was canceled with the token passed in through WithCancellation<TSource>(ParallelQuery<TSource>, CancellationToken).

ArgumentNullException

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

InvalidOperationException

source has more than one element.

AggregateException

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

See also

• Parallel LINQ (PLINQ)

SingleOrDefault<TSource>(ParallelQuery<TSource>, Func<TSource,Boolean>)

Source:

ParallelEnumerable.cs

Returns the only element of a parallel sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource SingleOrDefault(System::Linq::ParallelQuery<TSource> ^ source, Func<TSource, bool> ^ predicate);

public static TSource? SingleOrDefault<TSource> (this System.Linq.ParallelQuery<TSource> source, Func<TSource,bool> predicate);

static member SingleOrDefault : System.Linq.ParallelQuery<'Source> * Func<'Source, bool> -> 'Source

<Extension()>
Public Function SingleOrDefault(Of TSource) (source As ParallelQuery(Of TSource), predicate As Func(Of TSource, Boolean)) As TSource

Type Parameters

TSource

The type of the elements of source.

Parameters

source

ParallelQuery<TSource>

The sequence to return the single element of.

predicate

Func<TSource,Boolean>

A function to test an element for a condition.

Returns

TSource

The single element of the input sequence that satisfies the condition, or default() if no such element is found.

Exceptions

OperationCanceledException

The query was canceled with the token passed in through WithCancellation<TSource>(ParallelQuery<TSource>, CancellationToken).

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

source is empty or multiple elements are returned.

See also

• Parallel LINQ (PLINQ)