Richard I assume you created a project of type 'Class Library'. No you can't debug those, you need to host it in some other sort of exectuable project. To debug that you either need to add another project of a type that is executable to your solution (like a Windows Forms, WPF or Console application) and reference the output from the first project in that, so you can test it. You need to right-click on that project in Solution Explorer and select 'Set As Startup Project'.
Normally I would recommend to test it on the .NET side you actually use a proper testing framework like MSTest or NUnit. However what you're trying to really needs to be checked visually so that's probably overkill initially. Did you make the relevant methods COM-visible, i.e. like: [ComVisible(true)] [Guid("8C019E76-59BE-43A6-9DD9-66F7C9CAE67B")] [ProgId("MyApp.ExcelConvert")] [ClassInterface(ClassInterfaceType.AutoDual)] [ComSourceInterfaces(typeof(IExcelConvertEvents))] public class ExcelConvertHelper { ... } I must confess I've never gotten the wwDotNetBridge registration-free COM to work. I've always had to add an installer project in .NET and just make users install and register the assembly. Don't forget you have to build it as 32-bit to use it from VFP. -- Alan Bourke alanpbourke (at) fastmail (dot) fm _______________________________________________ Post Messages to: ProFox@leafe.com Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: https://leafe.com/archives This message: https://leafe.com/archives/byMID/48366147-3ce6-49f0-bc3c-6574dce98...@app.fastmail.com ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.