I am working on a web application that is used for migrating other web
applications to production.  The application currently loads each dll in the
target application using  Assembly.LoadFile and then calls
GetCustomAttributes on the assembly to ensure it was not built in debug mode.
 The problem with this approach is that it leaves the assembly loaded until
the worker process times out or is otherwise unloaded.

I need to be able to determine if the assembly was built in debug mode
without loading the assembly.   Because we, by policy, build Release mode
with "Generate Debugging Information" set to true, we have a .pdb file even
in release so checking for the existence of the .pdb is not an option.

I assume the approach would mean to open the file as a binary file, parse
the appropriate metadata elements, and then close the file.  Any ideas on how
to do read the metadata like this or on alternative methods to accomplish the
goal that leaves the target assembly files closed and unloaded?

Thanks in advance,

Dale