Observable.SelectMany<TSource, TCollection, TResult> Method (IObservable<TSource>, Func<TSource, IEnumerable<TCollection>>, Func<TSource, TCollection, TResult>)

Projects each element of an observable sequence to an observable sequence and flattens the resulting observable sequences into one observable sequence.

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

public static IObservable<TResult> SelectMany<TSource, TCollection, TResult>(
	this IObservable<TSource> source,
	Func<TSource, IEnumerable<TCollection>> collectionSelector,
	Func<TSource, TCollection, TResult> resultSelector

Type Parameters


The type of source.


The type of collection.


The type of result.


Type: System.IObservable<TSource>
An observable sequence of elements to project.
Type: System.Func<TSource, IEnumerable<TCollection>>
A transform function to apply to each element.
Type: System.Func<TSource, TCollection, TResult>
A transform function to apply to each element of the intermediate sequence.

Return Value

Type: System.IObservable<TResult>
An observable sequence whose elements are the result of invoking the one-to-many transform function collectionSelector on each element of the input sequence and then mapping each of those sequence elements and their corresponding source element to a result element.

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 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.