IAsyncCursorSourceExtensions.FirstOrDefaultAsync<TDocument> 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: 2.21.0+5a9c3311e158910b88195f290e6d4b1b2715d2b2

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.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 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 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).

Reference

IAsyncCursorSourceExtensions Class