We often think how to modify our code during writing, debugging, but rarely after assembly is built. Well, there are a few kinds of post-build manipulations we might want to perform on compiled assemblies:
This nice utility was developed by Mike Barnett from Microsoft Research and it enables merging multiple assemblies to a single one. This may be very useful, when one wants to deliver a single component or executable without exposing the internal structure of assemblies. It may be used as command-line utility (from post build action as well) and as a assembly reference and wrapped within another tool. It does not work on Silverlight assemblies, at least at the moment of writing these lines and I asked Mike to check this out.
Convert to Silverlight
This project developed by Suriel Bendahan enables converting assemblies compiled on server-side .NET to Silverlight compatible assemblies. It makes possible to reuse code written as "server-side" on Silverlight client. It might be useful for generic data structures, generic algorithms, input validations, sharing interfaces etc. The project is provided with it sources, so it can be modified/adopted for your needs.
Silverlight assemblies are being downloaded to browser in a XAP file, which is a bunch of DLLs compressed using ZIP compression. This project developed by Rob Houweling uncompresses these assemblies and compresses them again with a higher compression rate. This is very useful when XAP size becomes an issue.
Obfuscation is a process of changing the readability of the code without changing its functionality. The reason for doing this is preventing others from seeing implementation. Visual Studio comes with a Dotfuscator Community Edition and there are others providers of obfuscation utilities.