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

static member DefaultIfEmpty : 
        source:IQbservable<'TSource> * 
        defaultValue:'TSource -> IQbservable<'TSource> 

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.
defaultValue
Type: TSource
The value to return if the sequence is empty.

Return Value

Type: System.Reactive.Linq.IQbservable(TSource)
A queryable 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 IQbservable(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.
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