ASP.NET – AppDomain.CurrentDomain.GetAssemblies() – Assemblies missing after AppDomain restart

I have a Bootstrapper that looks through all Assemblies in an ASP.NET MVC application to find types that implement an IBootstrapperTask interface, and then registers them with an IOC Contrainer. The idea is that you can literaly place your IBootstrapperTasks anywhere, and organise your Projects how you please.

Error handling when downloading file from ASP.NET Web Handler (.ashx)

I have a web page which a user can download a PDF file via an ASP.NET web handler (.ashx). It is implemented like the answer in this question. The problem I have is when I do do this window.top.location.href = url; in my JavaScript I have no real control over what happens if there is an exception thrown in the handler. The user experience, when everything works correctly, is that they essentially stay on the page they were on and the browser tells them that they can download the PDF file. However, when there is an exception thrown in the handler they are redirected to the URL of the handler and shown a blank page.