PostSharp

[Ed_ward]

Hi guys

Could anyone describe me how to use AttributeTargetMemberAttributes property?
I want some attribute to be applied only to public methods of a class.

when I specify such attribute
[ValidateArguments( AttributeTargetMemberAttributes =
                             MulticastAttributes.All |
                            ~MulticastAttributes.Private |
                            ~MulticastAttributes.Protected)]
or
[ValidateArguments( AttributeTargetMemberAttributes =
                             MulticastAttributes.AnyVisibility |
                            ~MulticastAttributes.Private |
                            ~MulticastAttributes.Protected)]
on the class definition, this attribute is still applied to private methods of this class.
Ed.ward

[gfraiteur]

Ed,

It is a standard bit map where bits are grouped into the categories: visibility, virtuality, implementation, and scope.

I think what you want is:

or

[ValidateArguments( AttributeTargetMemberAttributes =

MulticastAttributes.NonAbstract |
MulticastAttributes.AnyScope |
( MulticastAttributes.AnyVisibility & ~MulticastAttributes.Private) |
MulticastAttributes.Managed )]

Why NonAbstract instead of AnyVirtuality and Managed instead of AnyImplementation? Because you derive your aspect from OnMethodBoundaryAspect, which has these limitations, and you are not allowed to enlarge the possible set of targets.

I ack there is a usability problem for this and I plan to make it easier.

Gael

[Ed_ward]

Ok, I see you point, but I want some more strange than you described

// attribute usages are skipped
public class ValidateArgumentsAttribute : MulticastAttribute, IRequirePostSharp
{
        public readonly Type ExceptionSpecializationType;


        public ValidateArgumentsAttribute( ) : this( null ){}
        public ValidateArgumentsAttribute( Type exceptionSpecializationType )
        {
            ExceptionSpecializationType = exceptionSpecializationType;
            AttributeReplace = true;

            AttributeTargetMemberAttributes = MulticastAttributes.NonAbstract    |                                                           MulticastAttributes.AnyScope |                                                       MulticastAttributes.Public        |
                                                      MulticastAttributes.Managed;
        }

        #region IRequirePostSharp Members
        //...
        #endregion
    }

    Please get a look at constructor of this attribute, I want to make "default" behaviour. Hence if I apply my attribute without any specifications
[ValidateArguments] I expect that it will not be applied to private methods, but I still want be able to apply this attribute to private members if I need.

    Unfortunately it does not work, but if I apply my attribute in such way (i.e. inside an AssemblyInfo)
[ValidateArguments(AttributeTargetMemberAttributes = MulticastAttributes.NonAbstract    |
                                                         
MulticastAttributes.AnyScope |
                                                     
MulticastAttributes.Public        |                                                      MulticastAttributes.Managed] it works as expected.

Actually, I cannot understand why it does not work...

Ed

[gfraiteur]

Yes, surely, it won't work. PostSharp does not execute the constructor of the custom attribute during the multicasting process. You have to set it in the CA instance.

That's why.

Any usability problem with that? I think your use case is covered by the [MulticastAttributeUsage] custom attribute.

Gael

[Edward]

Hi Gael, sorry for a very big delay

> Any usability problem with that? I think your use case is covered by the
> [MulticastAttributeUsage] custom attribute.

Unfortunately it isn't.
I want be able to apply my attribute to members with any visibility, but at the same time I want to have default behaviour - by default my attribute must be applied only to members with public visibility.
If I specify only public visibility in the MulticastAttributeUsage I won't be able to apply my attribute to the any private member, am I right?

Ed.ward

[gfraiteur]

So I think there is no solution to your problem. You cannot define a default behavior and give the possibility to override it,

Gael

[Ed_ward]

Ok, it is not a very big problem

Thanks Gael