MongoQueryable.SingleOrDefaultAsync(TSource) Method (IMongoQueryable(TSource), Expression(Func(TSource, Boolean)), CancellationToken) (original) (raw)
MongoQueryableSingleOrDefaultAsyncTSource Method (IMongoQueryableTSource, ExpressionFuncTSource, Boolean, CancellationToken)
Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.
Namespace: MongoDB.Driver.Linq
Assembly: MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.10.0+569905ff5e778c38ea19d9d0392496a83e1704ed
Syntax
public static Task SingleOrDefaultAsync( this IMongoQueryable source, Expression<Func<TSource, bool>> predicate, CancellationToken cancellationToken = null )
Public Shared Function SingleOrDefaultAsync(Of TSource) ( source As IMongoQueryable(Of TSource), predicate As Expression(Of Func(Of TSource, Boolean)), Optional cancellationToken As CancellationToken = Nothing ) As Task(Of TSource)[] static member SingleOrDefaultAsync : source : IMongoQueryable<'TSource> * predicate : Expression<Func<'TSource, bool>> * ?cancellationToken : CancellationToken (* Defaults: let _cancellationToken = defaultArg cancellationToken null *) -> Task<'TSource>
Parameters
source
Type: MongoDB.Driver.LinqIMongoQueryableTSource
An IMongoQueryableT to return a single element from.
predicate
Type: System.Linq.ExpressionsExpressionFuncTSource, Boolean
A function to test an element for a condition.
cancellationToken (Optional)
Type: System.ThreadingCancellationToken
The cancellation token.
Type Parameters
TSource
The type of the elements of source.
Return Value
Type: TaskTSource
The single element of the input sequence that satisfies the condition in predicate, or default(TSource) if no such element is found.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IMongoQueryableTSource. 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).
See Also