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DefaultIfEmpty(TSource) Method (IQbservable(TSource))

Qbservable.DefaultIfEmpty(TSource) Method (IQbservable(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.Providers (in System.Reactive.Providers.dll)

JScript does not support generic types and methods.

Type Parameters

TSource

The type of source.

Parameters

source
Type: System.Reactive.Linq.IQbservable(TSource)
The sequence to return a default value for if it is empty.

Return Value

Type: System.Reactive.Linq.IQbservable(TSource)
A queryable observable sequence that contains the default value for the TSource type 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 IQbservable(TSource). When you use instance method syntax to call this method, omit the first parameter. For more information, see https://msdn.microsoft.com/en-us/library/bb384936(v=vs.103).aspx or https://msdn.microsoft.com/en-us/library/bb383977(v=vs.103).aspx.
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