Thursday, February 23, 2006

COM+/Enterprise Services Configuration

COM+ application components can be configured two ways. They can be configured to run as library applications (in-process) or as a Server application (out of process). Having a library component isn’t a problem since it is running with the application domain as the calling application. However, getting configuration settings into a Server application can be a challenge. So much so, that I typically recommend running a COM+ applications as a library application.

So why is configuration so difficult for server application? Well I’m glad you asked. It’s because the server application is running in a process called dllhost.exe. This process lives in the {Windows}\System32\ directory. The .NET framework “automagically” loads the configuration file named dllhost.exe.config to get the configuration settings as long as it is in the System32 directory. This works great until you have 2 Server components that need different configuration settings. Do you see the problem? 2 Processes – 1 Configuration file. Plus most IT departments freak out (with good reason) when you need to deploy a file to the System32 directory.

If you’ve read this far you’ll find the purpose for this post. I had a colleague send me a link that documents how to use the new options in COM+ 1.5 to use the application directory. This is the only time I’ve heard about using the application.manifest and the application.config files.


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