IAggregateFluentExtensionsSingleOrDefaultAsyncTResult Method

Returns the only document of the aggregate result, or the default value if the result set is empty. Throws an exception if the result set contains more than one document.

Namespace: MongoDB.Driver
Assembly: MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.12.2+a4a3888f4fb51bb518b1eb5002effc2d47f2ea6a

Syntax

Copy

public static Task<TResult> SingleOrDefaultAsync<TResult>(
	this IAggregateFluent<TResult> aggregate,
	CancellationToken cancellationToken = null
)

<ExtensionAttribute>
Public Shared Function SingleOrDefaultAsync(Of TResult) ( 
	aggregate As IAggregateFluent(Of TResult),
	Optional cancellationToken As CancellationToken = Nothing
) As Task(Of TResult)

[<ExtensionAttribute>]
static member SingleOrDefaultAsync : 
        aggregate : IAggregateFluent<'TResult> * 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _cancellationToken = defaultArg cancellationToken null
*)
-> Task<'TResult>

Parameters

aggregate: Type: MongoDB.DriverIAggregateFluentTResult
The aggregate.
cancellationToken (Optional): Type: System.ThreadingCancellationToken
The cancellation token.

Type Parameters

TResult: The type of the result.

Return Value

Type: TaskTResult
The fluent aggregate interface.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IAggregateFluentTResult. 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

IAggregateFluentExtensions Class