IAsyncCursorSourceExtensionsSingleOrDefaultTDocument 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: 2.11.0+cb27a82ea70620ad1acad8058809be8302ae4f2a

Syntax

Copy

public static TDocument SingleOrDefault<TDocument>(
	this IAsyncCursorSource<TDocument> source,
	CancellationToken cancellationToken = null
)

<ExtensionAttribute>
Public Shared Function SingleOrDefault(Of TDocument) ( 
	source As IAsyncCursorSource(Of TDocument),
	Optional cancellationToken As CancellationToken = Nothing
) As TDocument

[<ExtensionAttribute>]
static member SingleOrDefault : 
        source : IAsyncCursorSource<'TDocument> * 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _cancellationToken = defaultArg cancellationToken null
*)
-> '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: TDocument
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 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).

Reference

IAsyncCursorSourceExtensions Class