EntityFrameworkQueryableExtensions.SingleAsync Method
Definition
Important
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Overloads
| SingleAsync<TSource>(IQueryable<TSource>, CancellationToken) |
Asynchronously returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence. |
| SingleAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken) |
Asynchronously 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>(IQueryable<TSource>, CancellationToken)
Asynchronously 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.Task<TSource> SingleAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Threading.CancellationToken cancellationToken = default);static member SingleAsync : System.Linq.IQueryable<'Source> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'Source><Extension()>
Public Function SingleAsync(Of TSource) (source As IQueryable(Of TSource), Optional cancellationToken As CancellationToken = Nothing) As Task(Of TSource)Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IQueryable<TSource>
An IQueryable<T> to return the single element of.
- cancellationToken
- CancellationToken
A CancellationToken to observe while waiting for the task to complete.
Returns
A task that represents the asynchronous operation. The task result contains the single element of the input sequence.
Exceptions
source is null.
If the CancellationToken is canceled.
Remarks
Multiple active operations on the same context instance are not supported. Use await to ensure that any asynchronous operations have completed before calling another method on this context. See Avoiding DbContext threading issues for more information and examples.
See Querying data with EF Core for more information and examples.
Applies to
SingleAsync<TSource>(IQueryable<TSource>, Expression<Func<TSource,Boolean>>, CancellationToken)
Asynchronously 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.Task<TSource> SingleAsync<TSource> (this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,bool>> predicate, System.Threading.CancellationToken cancellationToken = default);static member SingleAsync : System.Linq.IQueryable<'Source> * System.Linq.Expressions.Expression<Func<'Source, bool>> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'Source><Extension()>
Public Function SingleAsync(Of TSource) (source As IQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean)), Optional cancellationToken As CancellationToken = Nothing) As Task(Of TSource)Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IQueryable<TSource>
An IQueryable<T> to return the single element of.
- predicate
- Expression<Func<TSource,Boolean>>
A function to test an element for a condition.
- cancellationToken
- CancellationToken
A CancellationToken to observe while waiting for the task to complete.
Returns
A task that represents the asynchronous operation.
The task result contains the single element of the input sequence that satisfies the condition in
predicate.
Exceptions
source or predicate is null.
No element satisfies the condition in predicate.
-or-
More than one element satisfies the condition in predicate.
-or-
source contains no elements.
If the CancellationToken is canceled.
Remarks
Multiple active operations on the same context instance are not supported. Use await to ensure that any asynchronous operations have completed before calling another method on this context. See Avoiding DbContext threading issues for more information and examples.
See Querying data with EF Core for more information and examples.
Applies to
Entity Framework