IAsyncCursorSourceExtensionsFirstOrDefaultAsyncTDocument Method |
Returns the first document of a cursor returned by a cursor source, or a default value if the cursor contains no documents.
Namespace:
MongoDB.Driver
Assembly:
MongoDB.Driver.Core (in MongoDB.Driver.Core.dll) Version: 2.19.1+3a2a09dd959482f665ffbb5df2557ec541597af4
Syntax public static Task<TDocument> FirstOrDefaultAsync<TDocument>(
this IAsyncCursorSource<TDocument> source,
CancellationToken cancellationToken = default
)
<ExtensionAttribute>
Public Shared Function FirstOrDefaultAsync(Of TDocument) (
source As IAsyncCursorSource(Of TDocument),
Optional cancellationToken As CancellationToken = Nothing
) As Task(Of TDocument)
[<ExtensionAttribute>]
static member FirstOrDefaultAsync :
source : IAsyncCursorSource<'TDocument> *
?cancellationToken : CancellationToken
(* Defaults:
let _cancellationToken = defaultArg cancellationToken new CancellationToken()
*)
-> Task<'TDocument>
Parameters
- source
- Type: MongoDB.DriverIAsyncCursorSourceTDocument
The source. - cancellationToken (Optional)
- Type: System.ThreadingCancellationToken
The cancellation token.
Type Parameters
- TDocument
- The type of the document.
Return Value
Type:
TaskTDocumentA Task whose result is the first document of the 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
IAsyncCursorSourceTDocument. 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