PostSharp

Aspect Classes

The following table gives a list of available primitive aspect classes. Every aspect class is described in greater detailed in the class reference documentation.

Aspect Type	Targets	Description
OnMethodBoundaryAspect	Methods	Methods enhanced with an OnMethodBoundaryAspect are wrapped by a try/catch/finally construct. This aspect provides the advices OnEntry(MethodExecutionArgs), OnSuccess(MethodExecutionArgs), OnException(MethodExecutionArgs) and OnExit(MethodExecutionArgs); these advices are invoked directly from the transformed method. the return value, and the exception (if applicable). This aspect is useful to implement tracing or transaction handling, for instance.
OnExceptionAspect	Methods	Methods enhanced with an OnExceptionAspect are wrapped by a try/catch construct. This aspect provides the advice OnException(MethodExecutionArgs); this advice is invoked from the catch block. This aspect is useful to implement exception handling policies. Contrarily to OnMethodBoundaryAspect, this aspect lets you define the type of caught exceptions by overriding the method GetExceptionType(MethodBase)
MethodInterceptionAspect	Methods	When a method is enhanced by a MethodInterceptionAspect, all calls to this method are replaced by calls to OnInvoke(MethodInterceptionArgs), the only advice of this aspect type. This aspect is useful when the execution of target method can be deferred (asynchronous calls), must be dispatched on a different thread.
LocationInterceptionAspect	Fields, Properties	When a field or property is enhanced by a LocationInterceptionAspect, all calls to its accessors are replaced by calls to advices OnGetValue(LocationInterceptionArgs) and OnSetValue(LocationInterceptionArgs). Fields are transparently replaced by properties. This aspect is useful to implement functionalities that need to get or set the location value, such as the observability design pattern (INotifyPropertyChanged).
EventInterceptionAspect	Events	When an event is enhanced by an EventInterceptionAspect, all calls to its add and remove semantics are replaced by calls to advices OnAddHandler(EventInterceptionArgs) and OnRemoveHandler(EventInterceptionArgs). Additionally, when the event is fired, even of invoking directly the handlers that were added to the event, the advice OnInvokeHandler(EventInterceptionArgs) is called instead. This aspect is useful to add functionalities to events, such as implementing asynchronous events or materialized list of subscribers.
CompositionAspect	Types	This aspect introduces an interface into a type by composition. The interface is introduced statically; the aspect method GetPublicInterfaces(Type) should return the type of introduced interfaces. However, the object implementing the interface is created dynamically at runtime by the implementation of the method CreateImplementationObject(AdviceArgs).
CustomAttributeIntroductionAspect	Any	This aspect introduces a custom attribute on any element of code. A custom attribute can be represented as a CustomAttributeData or a ObjectConstruction.
ManagedResourceIntroductionAspect	Assemblies	This aspect introduces a managed resource into the current assembly.

Tip

The implementation of aspects OnMethodBoundaryAspect and OnExceptionAspect is very efficient; they should be preferred over other aspects whenever it makes sense.