IAsyncCursorSourceExtensionsFirstOrDefaultTDocument 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: 2.17.0+b316340e6cc3a8bfc8638dc31b54fbbfe41bfcb2

Syntax

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public static TDocument FirstOrDefault<TDocument>(
	this IAsyncCursorSource<TDocument> source,
	CancellationToken cancellationToken = default
)

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

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