durable OO designs in VB6

Question

I would like some contributions on how I can design a new VB winforms application that is easy to migrate to .NET. My current work environment dictate use of VB6 but I know they have plans to go to .NET when management is ready to do so. There is no way I should even try to suggest do it once in .NET now. It is not on. I would therefore need to setup a VB6 architecture that is relatively .NET friendly. This has to be balanced with the payback that can be quantified for extra development efforts needed now. I know these aspects of the VB6 application: 1) It has to use some 3rd ActiveX addons, these include TrueDBGrid, Farpoint Tabpro and Crystal 8.5; 2) It has to do automation stuff to integrate functions from Word, and maybe outlook to send mail. Database would be SQL2K through ADO (not the .NET version); 3) It may have to use some Windows API, although such would be minimized if possible; 4) This moderately complicated application will have 10 or less concurrent users, no need for specialised security, and performance is probably not a big issue; 5) usability of the application has to be high, and development/maintenance costs has to be as low as possible. I think it is possible to have a future scenario where parts of this application could be using .NET services (e.g. ADO.NET) and portions retained in the ActiveX arena, particularly if there are use of 3rd party tool not already available in a future .NET environment. The enduser should not have to change work habbits where practicable. Thank you all in advance for contributions related to the architecture of this inhouse VB6 application. David 10Nov 2003