)} ,--0)}

Observable.DefaultIfEmpty(IObservable) method¶

Defined in

Type: Observable Namespace: System.Reactive.Linq Assembly: System.Reactive.dll

Applies to

netstandard2.0

Overloads¶

1. public static IObservable<TSource?> DefaultIfEmpty<TSource>(this IObservable<TSource> source)
2. public static IObservable<TSource> DefaultIfEmpty<TSource>(this IObservable<TSource> source, TSource defaultValue)

1. Overload¶

public static IObservable<TSource?> DefaultIfEmpty<TSource>(this IObservable<TSource> source)

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

Type parameters

Name	Description
`TSource`	The type of the elements in the source sequence (if any), whose default value will be taken if the sequence is empty.

Parameters

Name	Type	Description
`source`	IObservable	The sequence to return a default value for if it is empty.

Returns: IObservable -- An observable sequence that contains the default value for the TSource type if the source is empty; otherwise, the elements of the source itself.

Exceptions

Type	Condition
System.ArgumentNullException	`source` is null.

2. Overload¶

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

Summary: Returns the elements of the specified sequence or the specified value in a singleton sequence if the sequence is empty.

Type parameters

Name	Description
`TSource`	The type of the elements in the source sequence (if any), and the specified default value which will be taken if the sequence is empty.

Parameters

Name	Type	Description
`source`	IObservable	The sequence to return the specified value for if it is empty.
`defaultValue`	`TSource`	The value to return if the sequence is empty.

Returns: IObservable -- An observable sequence that contains the specified default value if the source is empty; otherwise, the elements of the source itself.

Exceptions

Type	Condition
System.ArgumentNullException	`source` is null.