Observable.SingleOrDefault<TSource> Method (IObservable<TSource>)
Returns the only element of an observable sequence, or a default value if the observable sequence is empty.
Namespace: System.Reactive.Linq
Assembly: System.Reactive (in System.Reactive.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function SingleOrDefault(Of TSource) ( _
source As IObservable(Of TSource) _
) As TSource
'Usage
Dim source As IObservable(Of TSource)
Dim returnValue As TSource
returnValue = source.SingleOrDefault()
public static TSource SingleOrDefault<TSource>(
this IObservable<TSource> source
)
[ExtensionAttribute]
public:
generic<typename TSource>
static TSource SingleOrDefault(
IObservable<TSource>^ source
)
static member SingleOrDefault :
source:IObservable<'TSource> -> 'TSource
JScript does not support generic types and methods.
Type Parameters
- TSource
The type of source.
Parameters
- source
Type: System.IObservable<TSource>
The source observable sequence.
Return Value
Type: TSource
The single element in the observable sequence, or a default value if no value is found.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IObservable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see or .