IAsyncCursorExtensionsSingleOrDefaultAsyncTDocument Method

Returns the only document of a cursor, 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: 2.16.0+eeafbea0921243a5868b81984e1083a07c1f75bc

Syntax

Copy

public static Task<TDocument> SingleOrDefaultAsync<TDocument>(
	this IAsyncCursor<TDocument> cursor,
	CancellationToken cancellationToken = default
)

<ExtensionAttribute>
Public Shared Function SingleOrDefaultAsync(Of TDocument) ( 
	cursor As IAsyncCursor(Of TDocument),
	Optional cancellationToken As CancellationToken = Nothing
) As Task(Of TDocument)

[<ExtensionAttribute>]
static member SingleOrDefaultAsync : 
        cursor : IAsyncCursor<'TDocument> * 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _cancellationToken = defaultArg cancellationToken new CancellationToken()
*)
-> Task<'TDocument>

Parameters

cursor: Type: MongoDB.DriverIAsyncCursorTDocument
The cursor.
cancellationToken (Optional): Type: System.ThreadingCancellationToken
The cancellation token.

Type Parameters

TDocument: The type of the document.

Return Value

Type: TaskTDocument
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 IAsyncCursorTDocument. 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).

Reference

IAsyncCursorExtensions Class