Applying an aspect defined in one project to methods in other solution projects

Question

I created an aspect class inherited from the OnMethodBoundaryAspect of Postsharp class. When I use an aspect in the same project where I defined it, it works fine. But when I use this aspect in another project in my solution, this aspect will not apply. In this case, PostSharp Explorer says: “There is no aspect in the current solution ...” How can I solve this problem and use my aspect defined in project A, the methods or classes of project B in my solution? Thanks