AsyncEnumerable.SingleAsync Method

Definition

Namespace:

System.Linq

Assembly:

System.Linq.AsyncEnumerable.dll

Package:

System.Linq.AsyncEnumerable v10.0.0-preview.1.25080.5

Overloads

SingleAsync<TSource>(IAsyncEnumerable<TSource>, CancellationToken)	Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.
SingleAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,Boolean>, CancellationToken)	Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.
SingleAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<Boolean>>, CancellationToken)	Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.

SingleAsync<TSource>(IAsyncEnumerable<TSource>, CancellationToken)

Source:

SingleAsync.cs

Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.

public static System.Threading.Tasks.ValueTask<TSource> SingleAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Threading.CancellationToken cancellationToken = default);

static member SingleAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source>

<Extension()>
Public Function SingleAsync(Of TSource) (source As IAsyncEnumerable(Of TSource), Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of TSource)

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IAsyncEnumerable<TSource>

An IAsyncEnumerable<T> to return the single element of.

cancellationToken

CancellationToken

The CancellationToken to monitor for cancellation requests. The default is None.

Returns

ValueTask<TSource>

The single element of the input sequence.

Exceptions

ArgumentNullException

source is null.

InvalidOperationException

The source sequence contains more than one element. (via the returned task).

SingleAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,Boolean>, CancellationToken)

Source:

SingleAsync.cs

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

public static System.Threading.Tasks.ValueTask<TSource> SingleAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,bool> predicate, System.Threading.CancellationToken cancellationToken = default);

static member SingleAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, bool> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source>

<Extension()>
Public Function SingleAsync(Of TSource) (source As IAsyncEnumerable(Of TSource), predicate As Func(Of TSource, Boolean), Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of TSource)

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IAsyncEnumerable<TSource>

An IAsyncEnumerable<T> to return the single element of.

predicate

Func<TSource,Boolean>

A function to test an element for a condition.

cancellationToken

CancellationToken

The CancellationToken to monitor for cancellation requests. The default is None.

Returns

ValueTask<TSource>

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

Exceptions

ArgumentNullException

predicate is null.

InvalidOperationException

More than one element satisfies the condition in predicate (via the returned task).

SingleAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<Boolean>>, CancellationToken)

Source:

SingleAsync.cs

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

public static System.Threading.Tasks.ValueTask<TSource> SingleAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,System.Threading.CancellationToken,System.Threading.Tasks.ValueTask<bool>> predicate, System.Threading.CancellationToken cancellationToken = default);

static member SingleAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<bool>> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source>

<Extension()>
Public Function SingleAsync(Of TSource) (source As IAsyncEnumerable(Of TSource), predicate As Func(Of TSource, CancellationToken, ValueTask(Of Boolean)), Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of TSource)

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IAsyncEnumerable<TSource>

An IAsyncEnumerable<T> to return the single element of.

predicate

Func<TSource,CancellationToken,ValueTask<Boolean>>

A function to test an element for a condition.

cancellationToken

CancellationToken

The CancellationToken to monitor for cancellation requests. The default is None.

Returns

ValueTask<TSource>

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

Exceptions

ArgumentNullException

predicate is null.

InvalidOperationException

More than one element satisfies the condition in predicate (via the returned task).