.NET MEF DirectoryCatalog issue

Question

I am developing Excel add-in and use MEF to provide extensibility. DirectoryCatalog works fine on my local drive, however when I deploy solution to the network drive composition silently fails. In regular .exe application this problem can be resolved by adding "loadFromExternalSources=true" to "runtime" section of application configuration file, however for Excel add-in this file does not exist (and I can't add Excel.exe.config to the folder, containing Excel executable since this folder is read-only). Is there any way to programmatically enable loadFromExternalSources behavior?

Answer 1

Is there any way to programmatically enable loadFromExternalSources behavior?

If you create a seperate AppDomain with AppDomain.CreateDomain, then you can pass a AppDomainSetup which has a ConfigurationFile property.

However, I suppose that comvisible objects are normally created in the default appdomain so making the new AppDomain talk to Excel will probably be difficult. I guess it would involve shim classes in the default appdomain which pass calls through to the other appdomain.