.NET Assembly with COM compatibility problems

[simonm]

I have . VB.NET DLL that I have made COM visible and it works fine.

However, I've now added another class which I also want to expose to COM but I am now getting an erro when I build it:

Error 1 The assembly {...} could not be converted to a type library. Type library exporter encountered an error while processing 'TOPSMileageLookup.JobMileage, TOPSMileageLookup'. Error: Type 'JobMileage' and type 'Job' both have the same UUID.

JobMileage is the name of the original class I had that is COM visible and it worked fine when it was on it's own. Job is the name of the new class.

Now, the obvious suspician is that I have copied over my COM GUID's but I can assure you that they are most certainly different. But what else could it be?

[Max Peck]

Hmm ... that does sound like the build thinks the GUID is the same.

Have you tried doing a solution "clean"? Do that and a "rebuild" (rather than a build). It might be that an earlier build registered this guy for COM but the new one (with the new function) has a different interface but is trying to register it under the same GUID. The "clean" operation should unregister the COM interface before doing the rebuild.

-Max

[simonm]

I've tried doing a rebuild, but with the same result.

I've also tried changing the GUID's of the original class but again with no beneficial result.

I'm at a loss for what to try. Does anyone know if there's a limit to how many classes .NET allows to be COM visible (and this is it's round about way of telling me)?