Observable.TakeWhile<TSource> Method (IObservable<TSource>, Func<TSource, Int32, Boolean>)

Returns values from an observable sequence as long as a specified condition is true, and then skips the remaining values.

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

public static IObservable<TSource> TakeWhile<TSource>(
	this IObservable<TSource> source,
	Func<TSource, int, bool> predicate

Type Parameters


The type source.


Type: System.IObservable<TSource>
A sequence to return elements from.
Type: System.Func<TSource, Int32, Boolean>
True to the function to test each element for a condition; the second parameter of the function represents the index of the source element; otherwise, false.

Return Value

Type: System.IObservable<TSource>
An observable sequence that contains the elements from the input sequence that occur before the element at which the test no longer passes.

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.