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: 2.5.0+57.Branch.master.Sha.6a4e00a2d91090c65a9b11364b9ebfdb9c7da076

Syntax

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

<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 null
*)
-> 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: TaskTDocument
A 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).

Reference

IAsyncCursorSourceExtensions Class