AsyncEnumerable.LastOrDefaultAsync Method
Definition
Important
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Overloads
| LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<Boolean>>, TSource, CancellationToken) |
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found. |
| LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,Boolean>, TSource, CancellationToken) |
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found. |
| LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, TSource, CancellationToken) |
Returns the last element of a sequence, or a default value if the sequence contains no elements. |
| LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,Boolean>, CancellationToken) |
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found. |
| LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, CancellationToken) |
Returns the last element of a sequence, or a default value if the sequence contains no elements. |
| LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<Boolean>>, CancellationToken) |
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found. |
LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<Boolean>>, TSource, CancellationToken)
- Source:
- LastAsync.cs
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.
public static System.Threading.Tasks.ValueTask<TSource> LastOrDefaultAsync<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 LastOrDefaultAsync : 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 LastOrDefaultAsync(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
- source
- IAsyncEnumerable<TSource>
An IAsyncEnumerable<T> to return an element from.
- predicate
- Func<TSource,CancellationToken,ValueTask<Boolean>>
A function to test each element for a condition.
- defaultValue
- TSource
The default value to return if the sequence is empty.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
defaultValue if the sequence is empty or if no elements pass the test in the predicate function; otherwise, the last element that passes the test in the predicate function.
Exceptions
predicate is null.
Applies to
LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,Boolean>, TSource, CancellationToken)
- Source:
- LastAsync.cs
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.
public static System.Threading.Tasks.ValueTask<TSource> LastOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,bool> predicate, TSource defaultValue, System.Threading.CancellationToken cancellationToken = default);static member LastOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, bool> * 'Source * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function LastOrDefaultAsync(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
- source
- IAsyncEnumerable<TSource>
An IAsyncEnumerable<T> to return an element from.
- defaultValue
- TSource
The default value to return if the sequence is empty.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
defaultValue if the sequence is empty or if no elements pass the test in the predicate function; otherwise, the last element that passes the test in the predicate function.
Exceptions
predicate is null.
Applies to
LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, TSource, CancellationToken)
- Source:
- LastAsync.cs
Returns the last element of a sequence, or a default value if the sequence contains no elements.
public static System.Threading.Tasks.ValueTask<TSource> LastOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, TSource defaultValue, System.Threading.CancellationToken cancellationToken = default);static member LastOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * 'Source * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function LastOrDefaultAsync(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
- source
- IAsyncEnumerable<TSource>
An IAsyncEnumerable<T> to return the last element of.
- defaultValue
- TSource
The default value to return if the sequence is empty.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
defaultValue if the source sequence is empty; otherwise, the last element in the IAsyncEnumerable<T>.
Exceptions
source is null.
Applies to
LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,Boolean>, CancellationToken)
- Source:
- LastAsync.cs
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.
public static System.Threading.Tasks.ValueTask<TSource?> LastOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,bool> predicate, System.Threading.CancellationToken cancellationToken = default);static member LastOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, bool> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function LastOrDefaultAsync(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 an element from.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
The default value of TSource if the sequence is empty or if no elements pass the test in the predicate function; otherwise, the last element that passes the test in the predicate function.
Exceptions
predicate is null.
Applies to
LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, CancellationToken)
- Source:
- LastAsync.cs
Returns the last element of a sequence, or a default value if the sequence contains no elements.
public static System.Threading.Tasks.ValueTask<TSource?> LastOrDefaultAsync<TSource>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, System.Threading.CancellationToken cancellationToken = default);static member LastOrDefaultAsync : System.Collections.Generic.IAsyncEnumerable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<'Source><Extension()>
Public Function LastOrDefaultAsync(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 an element from.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
The default value of TSource if the source sequence is empty;
otherwise, the last element in the IAsyncEnumerable<T>.
Exceptions
source is null.
Applies to
LastOrDefaultAsync<TSource>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<Boolean>>, CancellationToken)
- Source:
- LastAsync.cs
Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.
public static System.Threading.Tasks.ValueTask<TSource?> LastOrDefaultAsync<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 LastOrDefaultAsync : 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 LastOrDefaultAsync(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 an element from.
- predicate
- Func<TSource,CancellationToken,ValueTask<Boolean>>
A function to test each element for a condition.
- cancellationToken
- CancellationToken
The CancellationToken to monitor for cancellation requests. The default is None.
Returns
The default value of TSource if the sequence is empty or if no elements pass the test in the predicate function; otherwise, the last element that passes the test in the predicate function.
Exceptions
predicate is null.
