Observable.DistinctUntilChanged(TSource, TKey) Method (IObservable(TSource), Func(TSource, TKey))

Returns an observable sequence that contains only distinct contiguous elements according to the keySelector.

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

JScript does not support generic types and methods.

Type Parameters


The type of source.


The type of key.


Type: System.IObservable(TSource)
An observable sequence to retain distinct contiguous elements for, based on a computed key value.
Type: System.Func(TSource, TKey)
A function to compute the comparison key for each element.

Return Value

Type: System.IObservable(TSource)
An observable sequence only containing the distinct contiguous elements, based on a computed key value from the source sequence.

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.