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
- source
Type: System.Reactive.Linq.IQbservable<TSource>
A queryable observable sequence whose elements to group.
- keySelector
Type: System.Linq.Expressions.Expression<Func<TSource, TKey>>
A function to extract the key for each element.
- elementSelector
Type: System.Linq.Expressions.Expression<Func<TSource, TElement>>
A function to map each source element to an element in an observable group.
- comparer
Type: System.Collections.Generic.IEqualityComparer<TKey>
An equality comparer to compare keys with.
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 .