Qbservable.FromEvent<TDelegate, TEventArgs> Method (IQbservableProvider, Expression<Func<Action<TEventArgs>, TDelegate>>, Expression<Action<TDelegate>>, Expression<Action<TDelegate>>)
Converts a .NET event to a queryable observable sequence.
Namespace: System.Reactive.Linq
Assembly: System.Reactive.Providers (in System.Reactive.Providers.dll)
Syntax
'Declaration
<ExtensionAttribute> _
Public Shared Function FromEvent(Of TDelegate, TEventArgs) ( _
provider As IQbservableProvider, _
conversion As Expression(Of Func(Of Action(Of TEventArgs), TDelegate)), _
addHandler As Expression(Of Action(Of TDelegate)), _
removeHandler As Expression(Of Action(Of TDelegate)) _
) As IQbservable(Of TEventArgs)
'Usage
Dim provider As IQbservableProvider
Dim conversion As Expression(Of Func(Of Action(Of TEventArgs), TDelegate))
Dim addHandler As Expression(Of Action(Of TDelegate))
Dim removeHandler As Expression(Of Action(Of TDelegate))
Dim returnValue As IQbservable(Of TEventArgs)
returnValue = provider.FromEvent(conversion, _
addHandler, removeHandler)
public static IQbservable<TEventArgs> FromEvent<TDelegate, TEventArgs>(
this IQbservableProvider provider,
Expression<Func<Action<TEventArgs>, TDelegate>> conversion,
Expression<Action<TDelegate>> addHandler,
Expression<Action<TDelegate>> removeHandler
)
[ExtensionAttribute]
public:
generic<typename TDelegate, typename TEventArgs>
static IQbservable<TEventArgs>^ FromEvent(
IQbservableProvider^ provider,
Expression<Func<Action<TEventArgs>^, TDelegate>^>^ conversion,
Expression<Action<TDelegate>^>^ addHandler,
Expression<Action<TDelegate>^>^ removeHandler
)
static member FromEvent :
provider:IQbservableProvider *
conversion:Expression<Func<Action<'TEventArgs>, 'TDelegate>> *
addHandler:Expression<Action<'TDelegate>> *
removeHandler:Expression<Action<'TDelegate>> -> IQbservable<'TEventArgs>
JScript does not support generic types and methods.
Type Parameters
- TDelegate
The type of delegate.
- TEventArgs
The type of event.
Parameters
- provider
Type: System.Reactive.Linq.IQbservableProvider
The local Qbservable provider.
- conversion
Type: System.Linq.Expressions.Expression<Func<Action<TEventArgs>, TDelegate>>
A function used to convert the given event handler to a delegate compatible with the underlying .NET event. The resulting delegate is used in calls to the addHandler and removeHandler action parameters.
- addHandler
Type: System.Linq.Expressions.Expression<Action<TDelegate>>
Action that attaches the given event handler to the underlying .NET event.
- removeHandler
Type: System.Linq.Expressions.Expression<Action<TDelegate>>
Action that detaches the given event handler from the underlying .NET event.
Return Value
Type: System.Reactive.Linq.IQbservable<TEventArgs>
The queryable observable sequence that contains data representations of invocations of the underlying .NET event.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IQbservableProvider. When you use instance method syntax to call this method, omit the first parameter. For more information, see or .