Hi,

I have seen a couple of threads dealing with similar questions, but I
haven't found one to answer my question, so here I go:

I have a service application that loads a couple of tasks (Plug-Ins you
might want to call them). When a task gets executed it will be executed
in its own AppDomain to allow

a) Easy unloading of DLLs
b) Version / Assembly independance to the controlling service

The service exposes a support object that implements a specific
interface. This object supports (for example) sending emails and relies
on a third party component for performing the SMTP tasks.

The interface reference to this object is passed to the tasks when
being executed (so we have one cross-appdomain call here). The tasks
perform their actions and might call back on the supplied interface
(cross-appdomain again).

However some tasks might require more improved email functionality. So
they link against that SMTP component themselves which might be
different to the version used by the service.

Problem is when one of these tasks actually calls back into the
supplied support object, the CLR comes back to me with a version /
assembly manifest mismatch exception. I would have thought that when I
return to the service AppDomain from my Task AppDomain I would be in
"safe land" as the object would be executed with any of its local
assemblies (no assembly is installed in the GAC), However to me it
seems that when the task calls back to the service, CLR attempts to
bind to the task's version of the SMTP component rather than the
service's component.

Is there any easy way I could get around this?

Thanks

Kai