AsyncEnumerable.SingleAsync Method
Definition
Important
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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
The single element of the input sequence.
Exceptions
source is null.
The source sequence contains more than one element. (via the returned task).
Applies to
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.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
The single element of the input sequence that satisfies a condition.
Exceptions
predicate is null.
More than one element satisfies the condition in predicate (via the returned task).
Applies to
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
The single element of the input sequence that satisfies a condition.
Exceptions
predicate is null.
More than one element satisfies the condition in predicate (via the returned task).
