We have many old COM classes that are still in use.  They were written in
VB6.  We are now starting to do some things in C# however we cannot just
throw away everything from COM and start over.  Our migration to C# will be
multi-phase and right now we just need proof of concept.  Here's our
situation:

1.  We need to create a DLL/TLB in C# that works in VB6
2.  C# class needs to implement a VB6 class interface
3.  C# class needs to be exported to COM TLB for use in VB6

Here is my basic code:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace UserBV
{  
   [ComVisible(true)]
   public class UserBVInput: AlfaBVIO.BVInput
   {
     
       [ComVisible(true)]
       void AlfaBVIO._BVInput.Initialize(ref DSDataObjects.DSDataType
iSettings)
       {
         
       }

       [ComVisible(true)]
       void AlfaBVIO._BVInput.GetScenarios(string iFileName, ref
System.Array oScenarios)
       {
       
       }

       
       public BVInput()
       {

       }
       
       ~BVInput()
       {

       }
   }

   [ComVisible(true)]
   public class BVOutput : AlfaBVIO.BVOutput
   {
       
       public BVOutput()
       {
           
       }
       
       ~BVOutput()
       {

       }

       [ComVisible(true)]
       void AlfaBVIO._BVOutput.Initialize(ref DSDataObjects.DSDataType
iSettings)
       {

       }

       [ComVisible(true)]
       void AlfaBVIO._BVOutput.Add(ref DSDataObjects.DSDataType
iFileHeader, ref DSDataObjects.DSDataType iBVSeries)
       {

       }

       [ComVisible(true)]
       void AlfaBVIO._BVOutput.Save()
       {

       }        
   }
}

I have the project file set according to "Register for COM interop" as well
as "Make assembly COM visible".  I am able to reference the built TLB file in
a VB6 project but there are no public methods.  The VB6 interface that I must
implement from is called AlfaBVIO.BVInput

Can someone please help me?  I'm sure to anyone that has experienced this
before it is a no-brainer.  This is just the first time I've ever had to do
something as odd as this.