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

CompositionAspect Class

Aspect that, when applied on a type, introduces one or many new interfaces into that type.
Inheritance Hierarchy
System.Object
  System.Attribute
    PostSharp.Extensibility.MulticastAttribute
      PostSharp.Aspects.Aspect
        PostSharp.Aspects.TypeLevelAspect
          PostSharp.Aspects.CompositionAspect

Namespace:  PostSharp.Aspects
Assembly:  PostSharp (in PostSharp.dll) Version: 5.0.39.0 (5.0.39.0)
Syntax
C#
[SerializableAttribute]
public abstract class CompositionAspect : TypeLevelAspect, 
	ICompositionAspect, ITypeLevelAspect, IAspect

The CompositionAspect type exposes the following members.

Constructors
  NameDescription
Protected methodCompositionAspect
Initializes a new instance of the CompositionAspect class
Properties
  NameDescription
Protected propertyAncestorOverrideAction
Specifies the action (Fail or Ignore) to be overtaken when an ancestor of one of the interfaces returned by GetPublicInterfaces(Type) is already implemented by the type to which the current aspect is applied.
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 propertyGenerateImplementationAccessor
Determines whether the interface [!:IComposed<T>] should be introduced into the type to which the aspect is applied for each interface returned by the GetPublicInterfaces(Type) method.
Protected propertyNonSerializedImplementation
Determines whether the field containing the interface implementation (and storing the object returned by CreateImplementationObject(AdviceArgs)) should be excluded from serialization by BinaryFormatter. The same effect is typically obtained by applying the NonSerializedAttribute custom attribute to the field.
Protected propertyOverrideAction
Specifies the action (Fail or Ignore) to be overtaken when one of the interfaces returned by the GetPublicInterfaces(Type) method is already implemented by the type to which the current aspect is applied.
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 TypeLevelAspect.)
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 TypeLevelAspect.)
Public methodCompileTimeValidate(Type)
Method invoked at build time to ensure that the aspect has been applied to the right target.
(Inherited from TypeLevelAspect.)
Protected methodCreateAspectConfiguration
Method invoked at build time to create a concrete AspectConfiguration instance specifically for the current Aspect type.
(Overrides Aspect.CreateAspectConfiguration().)
Public methodCreateImplementationObject
Method invoked at runtime, during the initialization of instances of the target type, to create the composed object.
Public methodGetAspectConfiguration
Method invoked at build tome to get the imperative configuration of the current Aspect.
(Inherited from Aspect.)
Protected methodGetPublicInterfaces
Gets the array of interfaces that should be introduced publicly into the target type of the current aspect.
Public methodRuntimeInitialize
Initializes the current aspect.
(Inherited from TypeLevelAspect.)
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, Type)
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.
(Overrides TypeLevelAspect.SetAspectConfiguration(AspectConfiguration, Type).)
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 TypeLevelAspect.)
Extension Methods
  NameDescription
Public Extension MethodQueryInterface<T>
Gets the implementation of a specified interface for the specified object.
(Defined by QueryInterfaceExtensions.)
Remarks
Note Note
Consider using a composite aspect and introducing an interface using IntroduceMemberAttribute instead of using a CompositionAspect.

The GetPublicInterfaces(Type) method is invoked at build time. At runtime, the method CreateImplementationObject(AdviceArgs) should return an object implementing all interfaces.

Use the Post.Cast<SourceType, TargetType>(SourceType) method to cast the enhanced type to the newly implemented interface. This cast is verified during post-compilation.

Properties OverrideAction and AncestorOverrideAction determine what should happen if the target type already implements the interface directly or indirectly.

By default, the object implementing the interface is stored as a serializable field. If the property NonSerializedImplementation is set to true, this field will be marked as NonSerializedAttribute.


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