Observable.GroupBy<TSource, TKey> Method (IObservable<TSource>, Func<TSource, TKey>)
Groups the elements of an observable sequence according to a specified key selector function.
Namespace: System.Reactive.Linq
Assembly: System.Reactive (in System.Reactive.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function GroupBy(Of TSource, TKey) ( _
source As IObservable(Of TSource), _
keySelector As Func(Of TSource, TKey) _
) As IObservable(Of IGroupedObservable(Of TKey, TSource))
'Usage
Dim source As IObservable(Of TSource)
Dim keySelector As Func(Of TSource, TKey)
Dim returnValue As IObservable(Of IGroupedObservable(Of TKey, TSource))
returnValue = source.GroupBy(keySelector)
public static IObservable<IGroupedObservable<TKey, TSource>> GroupBy<TSource, TKey>(
this IObservable<TSource> source,
Func<TSource, TKey> keySelector
)
[ExtensionAttribute]
public:
generic<typename TSource, typename TKey>
static IObservable<IGroupedObservable<TKey, TSource>^>^ GroupBy(
IObservable<TSource>^ source,
Func<TSource, TKey>^ keySelector
)
static member GroupBy :
source:IObservable<'TSource> *
keySelector:Func<'TSource, 'TKey> -> IObservable<IGroupedObservable<'TKey, 'TSource>>
JScript does not support generic types and methods.
Type Parameters
- TSource
The type source.
- TKey
The type key.
Parameters
- source
Type: System.IObservable<TSource>
An observable sequence whose elements to group.
- keySelector
Type: System.Func<TSource, TKey>
A function to extract the key for each element.
Return Value
Type: System.IObservable<IGroupedObservable<TKey, TSource>>
A sequence of observable groups, each of which corresponds to a unique key value, containing all elements that share that same key value.
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 or .