Post­Sharp Documentation / API Reference / Post­Sharp.​Aspects Namespace / Event­Interception­Aspect Class

EventInterceptionAspect Class

Aspect that, when applied on an event, intercepts invocations of its semantics Add (OnAddHandler(EventInterceptionArgs)), Remove (OnRemoveHandler(EventInterceptionArgs)) and Invoke (OnInvokeHandler(EventInterceptionArgs)).
Inheritance Hierarchy
System.Object
  System.Attribute
    PostSharp.Extensibility.MulticastAttribute
      PostSharp.Aspects.Aspect
        PostSharp.Aspects.EventLevelAspect
          PostSharp.Aspects.EventInterceptionAspect
            PostSharp.Patterns.Model.WeakEventAttribute

Namespace:  PostSharp.Aspects
Assembly:  PostSharp (in PostSharp.dll) Version: 5.0.39.0 (5.0.39.0)
Syntax
C#
[SerializableAttribute]
public abstract class EventInterceptionAspect : EventLevelAspect, 
	IEventInterceptionAspect, IEventLevelAspect, IAspect

The EventInterceptionAspect type exposes the following members.

Constructors
  NameDescription
Protected methodEventInterceptionAspect
Initializes a new instance of the EventInterceptionAspect class
Properties
  NameDescription
Public propertyAspectPriority
Gets or sets the weaving priority of the aspect.
(Inherited from Aspect.)
Public propertyAttributeExclude
If true, indicates that this attribute removes all other instances of the same attribute type from the set of elements defined by the current instance.
(Inherited from MulticastAttribute.)
Public propertyAttributeInheritance
Determines whether this attribute is inherited
(Inherited from MulticastAttribute.)
Public propertyAttributePriority
Gets or sets the priority of the current attribute in case that multiple instances are defined on the same element (lower values are processed before).
(Inherited from MulticastAttribute.)
Public propertyAttributeReplace
Determines whether this attribute replaces other attributes found on the target declarations.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetAssemblies
Gets or sets the assemblies to which the current attribute apply.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetElements
Gets or sets the kind of elements to which this custom attributes applies.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetExternalMemberAttributes
Gets or sets the visibilities, scopes, virtualities, and implementation of members to which this attribute applies, when the member is external to the current module.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetExternalTypeAttributes
Gets or sets the visibilities of types to which this attribute applies, when this type is external to the current module.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetMemberAttributes
Gets or sets the visibilities, scopes, virtualities, and implementation of members to which this attribute applies.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetMembers
Gets or sets the expression specifying to which members this instance applies.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetParameterAttributes
Gets or sets the passing style (by value, out or ref) of parameters to which this attribute applies.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetParameters
Gets or sets the expression specifying to which parameters this instance applies.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetTypeAttributes
Gets or sets the visibilities of types to which this attribute applies.
(Inherited from MulticastAttribute.)
Public propertyAttributeTargetTypes
Gets or sets the expression specifying to which types this instance applies.
(Inherited from MulticastAttribute.)
Protected propertySerializerType
Gets or sets the Type of the serializer (a type derived from AspectSerializer) used to serialize the aspect instance at build time and deserialize it at runtime.
(Inherited from Aspect.)
Methods
  NameDescription
Public methodCompileTimeInitialize
Method invoked at build time to initialize the instance fields of the current aspect. This method is invoked before any other build-time method.
(Inherited from EventLevelAspect.)
Public methodCompileTimeValidate(Object)
Method invoked at build time to ensure that the aspect has been applied to the right target.
(Inherited from Aspect.)
Public methodCompileTimeValidate(Object)
Method invoked at build time to ensure that the aspect has been applied to the right target.
(Inherited from EventLevelAspect.)
Public methodCompileTimeValidate(EventInfo)
Method invoked at build time to ensure that the aspect has been applied to the right target.
(Inherited from EventLevelAspect.)
Protected methodCreateAspectConfiguration
Method invoked at build time to create a concrete AspectConfiguration instance specifically for the current Aspect type.
(Overrides Aspect.CreateAspectConfiguration().)
Public methodGetAspectConfiguration
Method invoked at build tome to get the imperative configuration of the current Aspect.
(Inherited from Aspect.)
Public methodOnAddHandler
Method invoked instead of the Add semantic of the event to which the current aspect is applied, i.e. when a new delegate is added to this event.
Public methodOnInvokeHandler
Method invoked when the event to which the current aspect is applied is fired, for each delegate of this event, and instead of invoking this delegate.
Public methodOnRemoveHandler
Method invoked instead of the Remove semantic of the event to which the current aspect is applied, i.e. when a delegate is removed from this event.
Public methodRuntimeInitialize
Initializes the current aspect.
(Inherited from EventLevelAspect.)
Protected methodSetAspectConfiguration(AspectConfiguration, Object)
Method invoked at build time to set up an AspectConfiguration object according to the current Aspect instance and a specified target element of the current aspect.
(Inherited from Aspect.)
Protected methodSetAspectConfiguration(AspectConfiguration, Object)
Method invoked at build time to set up an AspectConfiguration object according to the current Aspect instance and a specified target element of the current aspect.
(Inherited from EventLevelAspect.)
Protected methodSetAspectConfiguration(AspectConfiguration, EventInfo)
Method invoked at build time to set up an AspectConfiguration object according to the current Aspect instance and a specified target element of the current aspect.
(Inherited from EventLevelAspect.)
Extension Methods
  NameDescription
Public Extension MethodQueryInterface<T>
Gets the implementation of a specified interface for the specified object.
(Defined by QueryInterfaceExtensions.)
Remarks

Applying an aspect of type EventInterceptionAspect to an event results in the add and remove methods of the event to be replaced by a call to OnAddHandler(EventInterceptionArgs) and OnRemoveHandler(EventInterceptionArgs), respectively. The original accessor body is moved into new methods, which the aspect code can call by invoking ProceedAddHandler() or ProceedRemoveHandler().

The method OnInvokeHandler(EventInterceptionArgs), if defined, is called instead when the event is raised, once for every handler that has been added to the list. When you define OnInvokeHandler(EventInterceptionArgs) method, PostSharp will use a broker object to control access to the event; this broker object will be the unique subscriber of the event, and maintains its own list of subscribers.

Note Note
The aspect works only when caller code access the event through its add/remove semantics. It does not work when the caller code bypasses the event semantics and accesses directly its implementation (the underlying field of the event, typically). The C# compiler is known to bypass the semantics when the event is accessed directly from the class declaring it (it accesses directly the private field whenever it can).

Note Note
All classes implementing IAspect should typically be marked as serializable using the SerializableAttribute or PSerializableAttribute custom attribute . Fields that are only used at runtime (and unknown at compile-time) should be carefully marked with the NonSerializedAttribute or PNonSerializedAttribute custom attribute. When PostSharp is used on a platform that does not support aspect serialization (such as .NET Compact Framework, Silverlight, or Windows Phone), or when another aspect serializer is used, it is not necessary to mark the aspect class as serializable. For more information, see Aspect Serialization .

See Also