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UIElementRemoveHandler Method
 

Removes the specified routed event handler from this element.

Namespace:   System.Windows
Assembly:  PresentationCore (in PresentationCore.dll)

public void RemoveHandler(
	RoutedEvent routedEvent,
	Delegate handler
)
public:
virtual void RemoveHandler(
	RoutedEvent^ routedEvent,
	Delegate^ handler
) sealed
abstract RemoveHandler : 
        routedEvent:RoutedEvent *
        handler:Delegate -> unit
override RemoveHandler : 
        routedEvent:RoutedEvent *
        handler:Delegate -> unit
Public Sub RemoveHandler (
	routedEvent As RoutedEvent,
	handler As Delegate
)

Parameters

routedEvent
Type:

The identifier of the routed event for which the handler is attached.

handler
Type:

The specific handler implementation to remove from the event handler collection on this element.

The most common scenario for using this API is when you implement the common language runtime (CLR) "wrapper" event that is associated with a custom routed event, specifically when you implement the "remove" logic for handlers at the CLR level. The example that follows this remarks section illustrates this scenario.

Calling this method has no effect if there were no handlers registered with criteria that matches the input parameters for the method call.

If more than one handler is attached that matched the criteria, only the first handler in the event handler store is removed. This behavior is consistent with CLR behavior of the -= operator.

Neither routedEvent nor handler may be null. Attempting to provide either value as null will raise an exception.

This method ignores the handledEventsToo parameter information, which is provided if the handler was first added with the AddHandler signature that enables handling of already-handled events. Either type of handler is removed.

The following example uses RemoveHandler as part of an event wrapper definition.

public static readonly RoutedEvent TapEvent = EventManager.RegisterRoutedEvent(
    "Tap", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(MyButtonSimple));

// Provide CLR accessors for the event
public event RoutedEventHandler Tap
{
        add { AddHandler(TapEvent, value); } 
        remove { RemoveHandler(TapEvent, value); }
}
Public Shared ReadOnly TapEvent As RoutedEvent = EventManager.RegisterRoutedEvent("Tap", RoutingStrategy.Bubble, GetType(RoutedEventHandler), GetType(MyButtonSimple))

' Provide CLR accessors for the event
Public Custom Event Tap As RoutedEventHandler
    AddHandler(ByVal value As RoutedEventHandler)
        Me.AddHandler(TapEvent, value)
    End AddHandler

    RemoveHandler(ByVal value As RoutedEventHandler)
        Me.RemoveHandler(TapEvent, value)
    End RemoveHandler

    RaiseEvent(ByVal sender As Object, ByVal e As RoutedEventArgs)
        Me.RaiseEvent(e)
    End RaiseEvent
End Event
.NET Framework
Available since 3.0
Silverlight
Available since 3.0
Windows Phone Silverlight
Available since 7.0
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