RegisterClassHandler Method (Type, RoutedEvent, Delegate)

EventManager.RegisterClassHandler Method (Type, RoutedEvent, Delegate)

Registers a class handler for a particular routed event.

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

public static void RegisterClassHandler(
	Type classType,
	RoutedEvent routedEvent,
	Delegate handler
You cannot use methods in XAML.


Type: System.Type

The type of the class that is declaring class handling.

Type: System.Windows.RoutedEvent

The routed event identifier of the event to handle.

Type: System.Delegate

A reference to the class handler implementation.

Class handling is a feature that is available for routed events, including attached events that are implemented with routed event backing. A class handler is like a static handler that exists for all instances of the class. Because the handler is static, you cannot change instance properties directly with a class handler, but you can access instances through the sender parameter and/or the event data.

Class handlers are invoked before instance handlers. You can implement a class handler that has the behavior of marking the event as handled. Therefore, instance handlers for a class-handled event are not invoked unless the instance handlers register specifically for handled events.

Many of the WPF base element events provide class handling virtual methods. By overriding these methods in classes that inherit the base classes, you can implement class handling without calling RegisterClassHandler in static constructors. These class handling methods typically exist for input events and have names that start with "On" and end with the name of the event being class handled.

For more information about class handling, see Marking Routed Events as Handled, and Class Handling.

Using this signature, class handlers will be registered to invoke only in response to unhandled events. You can also register class handlers to invoke even if the event arguments are marked handled, by using the RegisterClassHandler(Type, RoutedEvent, Delegate, Boolean) signature, with handledEventsToo set to true.

The following example adds a handler for PreviewMouseLeftButtonDown, calling RegisterClassHandler.

static MyEditContainer()
  EventManager.RegisterClassHandler(typeof(MyEditContainer), PreviewMouseRightButtonDownEvent, new RoutedEventHandler(LocalOnMouseRightButtonDown));
internal static void LocalOnMouseRightButtonDown(object sender, RoutedEventArgs e)
  MessageBox.Show("this is invoked before the On* class handler on UIElement");
  //e.Handled = true; //uncommenting this would cause ONLY the subclass' class handler to respond

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0

Community Additions

© 2016 Microsoft