I was able to do this successfully with another project, but running into all kinds of problems on a new one.

I have a C# 4.0 project that has several interfaces and classes defined. Each interface has InterfaceType and Guid attributes defined, and each class has Guid, ClassInterface and ProgID attributes. The build succeeds and I can see the classes in the registry. However, when I instantiate the class in VFP and attempt to call a method, I get "Syntax Error".

My guess is that this might have something to do with my return values, since their type is of one of the interfaces. Example:

To support our working with multiple marketing vendors, I created an IMarketing interface and have a factory class that returns the correct class implementation based on the chosen marketing vendor. So, the factory return value is of type IMarketing.

On a related note, I have a method that returns a List[T] and another that accepts a List[T] as a parameter. What changes would I need to make to ensure VFP can work with these lists?

Yes, I'm aware of wwDotNetBridge (Hi Rick! :) ), but just wanted to see if I could get this to work via COM interop first, if possible.

Jon