EntityFrameworkQueryableExtensions.SingleAsync Method

Definition

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

Task<TSource>

A task that represents the asynchronous operation. The task result contains the single element of the input sequence.

Exceptions

source is null.

source contains more than one elements.

-or-

source contains no elements.

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.

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

Task<TSource>

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.

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.

Applies to