The recording of the first ever ReactiveUI virtual conference is available on our YouTube Channel.


Observable.ElementAtOrDefault<TSource> Method

Returns the element at a specified index in a sequence or a default value if the index is out of range.

Namespace:  System.Reactive.Linq
Assembly:  System.Reactive (in System.Reactive.dll)


<ExtensionAttribute> _
Public Shared Function ElementAtOrDefault(Of TSource) ( _
    source As IObservable(Of TSource), _
    index As Integer _
) As IObservable(Of TSource)
Dim source As IObservable(Of TSource)
Dim index As Integer
Dim returnValue As IObservable(Of TSource)

returnValue = source.ElementAtOrDefault(index)
public static IObservable<TSource> ElementAtOrDefault<TSource>(
    this IObservable<TSource> source,
    int index
generic<typename TSource>
static IObservable<TSource>^ ElementAtOrDefault(
    IObservable<TSource>^ source, 
    int index
static member ElementAtOrDefault : 
        source:IObservable<'TSource> * 
        index:int -> IObservable<'TSource> 
JScript does not support generic types and methods.

Type Parameters

  • TSource
    The type of source.


  • source
    Type: System.IObservable<TSource>
    The observable sequence to return the element from.

  • index
    Type: System.Int32
    The zero-based index of the element to retrieve.

Return Value

Type: System.IObservable<TSource>
An observable sequence that produces the element at the specified position in the source sequence or a default value if the index is outside the bounds of the source sequence.

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 .

See Also


Observable Class

System.Reactive.Linq Namespace