DbRawSqlQuery<TElement>.SingleOrDefaultAsync Method (CancellationToken)
[This page is specific to the Entity Framework version 6. The latest version is available as the 'Entity Framework' NuGet package. For more information about Entity Framework, see msdn.com/data/ef.]
Asynchronously 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.
Namespace: System.Data.Entity.Infrastructure
Assembly: EntityFramework (in EntityFramework.dll)
Syntax
'Declaration
Public Function SingleOrDefaultAsync ( _
cancellationToken As CancellationToken _
) As Task(Of TElement)
'Usage
Dim instance As DbRawSqlQuery
Dim cancellationToken As CancellationToken
Dim returnValue As Task(Of TElement)
returnValue = instance.SingleOrDefaultAsync(cancellationToken)
public Task<TElement> SingleOrDefaultAsync(
CancellationToken cancellationToken
)
public:
Task<TElement>^ SingleOrDefaultAsync(
CancellationToken cancellationToken
)
member SingleOrDefaultAsync :
cancellationToken:CancellationToken -> Task<'TElement>
public function SingleOrDefaultAsync(
cancellationToken : CancellationToken
) : Task<TElement>
Parameters
- cancellationToken
Type: System.Threading.CancellationToken
A CancellationToken to observe while waiting for the task to complete.
Return Value
Type: System.Threading.Tasks.Task<TElement>
A task that represents the asynchronous operation. The task result contains the single element of the query result, or default ( TElement ) if the sequence contains no elements.
Exceptions
| Exception | Condition |
|---|---|
| InvalidOperationException | The query result has more than one element. |
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.