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Qbservable.GroupBy<TSource, TKey, TElement> Method (IQbservable<TSource>, Expression<Func<TSource, TKey>>, Expression<Func<TSource, TElement>>, IEqualityComparer<TKey>)

Groups the elements of a queryable observable sequence according to a specified key selector function and comparer and selects the resulting elements by using a specified function.

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

Syntax

'Declaration
<ExtensionAttribute> _
Public Shared Function GroupBy(Of TSource, TKey, TElement) ( _
    source As IQbservable(Of TSource), _
    keySelector As Expression(Of Func(Of TSource, TKey)), _
    elementSelector As Expression(Of Func(Of TSource, TElement)), _
    comparer As IEqualityComparer(Of TKey) _
) As IQbservable(Of IGroupedObservable(Of TKey, TElement))
'Usage
Dim source As IQbservable(Of TSource)
Dim keySelector As Expression(Of Func(Of TSource, TKey))
Dim elementSelector As Expression(Of Func(Of TSource, TElement))
Dim comparer As IEqualityComparer(Of TKey)
Dim returnValue As IQbservable(Of IGroupedObservable(Of TKey, TElement))

returnValue = source.GroupBy(keySelector, _
    elementSelector, comparer)
public static IQbservable<IGroupedObservable<TKey, TElement>> GroupBy<TSource, TKey, TElement>(
    this IQbservable<TSource> source,
    Expression<Func<TSource, TKey>> keySelector,
    Expression<Func<TSource, TElement>> elementSelector,
    IEqualityComparer<TKey> comparer
)
[ExtensionAttribute]
public:
generic<typename TSource, typename TKey, typename TElement>
static IQbservable<IGroupedObservable<TKey, TElement>^>^ GroupBy(
    IQbservable<TSource>^ source, 
    Expression<Func<TSource, TKey>^>^ keySelector, 
    Expression<Func<TSource, TElement>^>^ elementSelector, 
    IEqualityComparer<TKey>^ comparer
)
static member GroupBy : 
        source:IQbservable<'TSource> * 
        keySelector:Expression<Func<'TSource, 'TKey>> * 
        elementSelector:Expression<Func<'TSource, 'TElement>> * 
        comparer:IEqualityComparer<'TKey> -> IQbservable<IGroupedObservable<'TKey, 'TElement>> 
JScript does not support generic types and methods.

Type Parameters

  • TSource
    The type source.
  • TKey
    The type key.
  • TElement
    The type element.

Parameters

Return Value

Type: System.Reactive.Linq.IQbservable<IGroupedObservable<TKey, TElement>>
A sequence of queryable 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 IQbservable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see or .

See Also

Reference

Qbservable Class

GroupBy Overload

System.Reactive.Linq Namespace