Export (0) Print
Expand All

Observable.DefaultIfEmpty<TSource> Method (IObservable<TSource>, TSource)

Returns the elements of the specified sequence or the type parameter's default value in a singleton sequence if the sequence is empty.

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

public static IObservable<TSource> DefaultIfEmpty<TSource>(
	this IObservable<TSource> source,
	TSource defaultValue
)

Type Parameters

TSource

The type of source.

Parameters

source
Type: System.IObservable<TSource>
The sequence to return the specified value for if it is empty.
defaultValue
Type: TSource
The value to return if the sequence is empty.

Return Value

Type: System.IObservable<TSource>
An observable sequence that contains the specified default value if the source is empty; otherwise, the elements of the source itself.

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 http://msdn.microsoft.com/en-us/library/bb384936(v=vs.103).aspx or http://msdn.microsoft.com/en-us/library/bb383977(v=vs.103).aspx.
Show:
© 2014 Microsoft