IAsyncCursorSourceExtensions.SingleOrDefaultAsync<TDocument> Method |
Returns the only document of a cursor returned by a cursor source, or a default value if the cursor contains no documents.
This method throws an exception if the cursor contains more than one document.
Namespace:
MongoDB.Driver
Assembly:
MongoDB.Driver.Core (in MongoDB.Driver.Core.dll) Version: 2.15.0+f503bf610759c13f78cff9a3c01e91453185d2ed
Syntax public static Task<TDocument> SingleOrDefaultAsync<TDocument>(
this IAsyncCursorSource<TDocument> source,
CancellationToken cancellationToken = default
)
<ExtensionAttribute>
Public Shared Function SingleOrDefaultAsync(Of TDocument) (
source As IAsyncCursorSource(Of TDocument),
Optional cancellationToken As CancellationToken = Nothing
) As Task(Of TDocument)
[<ExtensionAttribute>]
static member SingleOrDefaultAsync :
source : IAsyncCursorSource<'TDocument> *
?cancellationToken : CancellationToken
(* Defaults:
let _cancellationToken = defaultArg cancellationToken new CancellationToken()
*)
-> Task<'TDocument>
Parameters
- source
- Type: MongoDB.Driver.IAsyncCursorSource<TDocument>
The source. - cancellationToken (Optional)
- Type: System.Threading.CancellationToken
The cancellation token.
Type Parameters
- TDocument
- The type of the document.
Return Value
Type:
Task<TDocument>A Task whose result is the only document of a cursor, or a default value if the cursor contains no documents.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type
IAsyncCursorSource<TDocument>. When you use instance method syntax to call this method, omit the first parameter. For more information, see
Extension Methods (Visual Basic) or
Extension Methods (C# Programming Guide).
See Also