AsyncEnumerable.SingleOrDefaultAsync Method (System.Linq) (original) (raw)
Definition
Namespace:
Assembly:
System.Linq.AsyncEnumerable.dll
Package:
System.Linq.AsyncEnumerable v10.0.0-preview.4.25258.110
Important
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Overloads
| SingleOrDefaultAsync(IAsyncEnumerable, CancellationToken) | Returns the only element of a 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. |
|---|---|
| SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,Boolean>, CancellationToken) | Returns the only element of a 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. |
| SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,CancellationToken,ValueTask>, CancellationToken) | Returns the only element of a 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. |
| SingleOrDefaultAsync(IAsyncEnumerable, TSource, CancellationToken) | Returns the only element of a 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. |
| SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,Boolean>, TSource, CancellationToken) | Returns the only element of a 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. |
| SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,CancellationToken,ValueTask>, TSource, CancellationToken) | Returns the only element of a 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. |
SingleOrDefaultAsync(IAsyncEnumerable, CancellationToken)
Source:
Returns the only element of a 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 static System.Threading.Tasks.ValueTask<TSource?> SingleOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Threading.CancellationToken cancellationToken = default);static member SingleOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function SingleOrDefaultAsync(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
Returns
The single element of the input sequence, or the default value of TSourceif the sequence contains no elements.
Exceptions
The source sequence contains more than one element. (via the returned task).
Applies to
SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,Boolean>, CancellationToken)
Source:
Returns the only element of a 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 static System.Threading.Tasks.ValueTask<TSource?> SingleOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,bool> predicate, System.Threading.CancellationToken cancellationToken = default);static member SingleOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, bool> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function SingleOrDefaultAsync(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
predicate
A function to test an element for a condition.
Returns
The single element of the input sequence that satisfies the condition, or the default value ofTSource if no such element is found.
Exceptions
The input sequence contains more than one element.
Applies to
SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,CancellationToken,ValueTask>, CancellationToken)
Source:
Returns the only element of a 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 static System.Threading.Tasks.ValueTask<TSource?> SingleOrDefaultAsync<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 SingleOrDefaultAsync : 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 SingleOrDefaultAsync(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
Returns
The single element of the input sequence that satisfies the condition, or the default value ofTSource if no such element is found.
Exceptions
The input sequence contains more than one element.
Applies to
SingleOrDefaultAsync(IAsyncEnumerable, TSource, CancellationToken)
Source:
Returns the only element of a 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 static System.Threading.Tasks.ValueTask<TSource> SingleOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, TSource defaultValue, System.Threading.CancellationToken cancellationToken = default);static member SingleOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * 'Source * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function SingleOrDefaultAsync(Of TSource) (source As IAsyncEnumerable(Of TSource), defaultValue As TSource, Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of TSource)Type Parameters
TSource
The type of the elements of source.
Parameters
defaultValue
TSource
The default value to return if the sequence is empty.
Returns
The single element of the input sequence, or defaultValue if the sequence contains no elements.
Exceptions
The input sequence contains more than one element.
Applies to
SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,Boolean>, TSource, CancellationToken)
Source:
Returns the only element of a 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 static System.Threading.Tasks.ValueTask<TSource> SingleOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,bool> predicate, TSource defaultValue, System.Threading.CancellationToken cancellationToken = default);static member SingleOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, bool> * 'Source * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function SingleOrDefaultAsync(Of TSource) (source As IAsyncEnumerable(Of TSource), predicate As Func(Of TSource, Boolean), defaultValue As TSource, Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of TSource)Type Parameters
TSource
The type of the elements of source.
Parameters
predicate
A function to test an element for a condition.
defaultValue
TSource
The default value to return if the sequence is empty.
Returns
The single element of the input sequence that satisfies the condition, or defaultValue if no such element is found.
Exceptions
More than one element satisfies the condition in predicate.
Applies to
SingleOrDefaultAsync(IAsyncEnumerable, Func<TSource,CancellationToken,ValueTask>, TSource, CancellationToken)
Source:
Returns the only element of a 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 static System.Threading.Tasks.ValueTask<TSource> SingleOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,System.Threading.CancellationToken,System.Threading.Tasks.ValueTask<bool>> predicate, TSource defaultValue, System.Threading.CancellationToken cancellationToken = default);static member SingleOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<bool>> * 'Source * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function SingleOrDefaultAsync(Of TSource) (source As IAsyncEnumerable(Of TSource), predicate As Func(Of TSource, CancellationToken, ValueTask(Of Boolean)), defaultValue As TSource, Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of TSource)Type Parameters
TSource
The type of the elements of source.
Parameters
defaultValue
TSource
The default value to return if the sequence is empty.
Returns
The single element of the input sequence that satisfies the condition, or defaultValue if no such element is found.
Exceptions
More than one element satisfies the condition in predicate.