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

Filters the elements of an observable sequence based on a predicate by incorporating the element's index.

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

Syntax

'Declaration
<ExtensionAttribute> _
Public Shared Function Where(Of TSource) ( _
    source As IObservable(Of TSource), _
    predicate As Func(Of TSource, Integer, Boolean) _
) As IObservable(Of TSource)

'Usage
Dim source As IObservable(Of TSource)
Dim predicate As Func(Of TSource, Integer, Boolean)
Dim returnValue As IObservable(Of TSource)

returnValue = source.Where(predicate)

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

[ExtensionAttribute]
public:
generic<typename TSource>
static IObservable<TSource>^ Where(
    IObservable<TSource>^ source, 
    Func<TSource, int, bool>^ predicate
)

static member Where : 
        source:IObservable<'TSource> * 
        predicate:Func<'TSource, int, bool> -> IObservable<'TSource> 

JScript does not support generic types and methods.

Type Parameters

• TSource
  The type source.

Parameters

• source
  Type: System.IObservable<TSource>
  An observable sequence whose elements to filter.

• predicate
  Type: System.Func<TSource, Int32, Boolean>
  A function to test each source element for a condition; the second parameter of the function represents the index of the source element.

Return Value

Type: System.IObservable<TSource>
An observable sequence that contains elements from the input sequence that satisfy the condition.

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 .

See Also

Reference

Observable Class

Where Overload

System.Reactive.Linq Namespace