The default VB6 upgrades produced by gmStudio contain two kinds of code:
1) application logic and data structures produced by reading, interpreting, and rewriting your VB6 code.
2) stub classes that satisfy the VB6/COM dependencies that do not have a single direct functionally equivalent replacement in .NET. The stub code generated by the tool corresponds to the specific needs of your VB6 application.
Typically the resulting system will not run very far using stubs; but it is still a solid starting point for beginning an upgrade project. I think it will be particularly useful for what you plan to do: get a clean, complete baseline translation of the application logic, get it to build, and then re-engineer it along with some rework to functionally correct, maintainable C#.
In order to make the generated application run, the stub classes must be replaced with functional implementations. This can be done by finishing the stubs by hand, or by configuring the tool to rewrite the application logic to use some other new or existing functional .NET classes (Microsoft .NET assemblies, COM-interop assemblies, third-party assemblies, other in-house assemblies, etc.).
If you are considering the "finish the stubs by hand" option, you would benefit by using our implementation of the stubs. This is the MigrationSupport.dll assembly that is distributed with gmStudio. This assembly implements many VB6 intrinsic objects and methods as well as a replacement for the ADODB API using System.Data and SqlClient classes. You can see our MigrationSupport API at work in our standard samples. I encourage you to review the samples for more details https://portal.greatmigrations.com/display/GMG/Samples and I would be happy to do a web demo to show you more.
The standard license of the tool includes MigrationSupport.dll assembly that you may use in binary form with the upgraded code However, if you want to be able to modify the MigrationSupport code, you should purchase a license for the source. A perpetual license to the C# source code of MigrationSupport.DLL is available to gmStudio customers. I have attached code metrics for the C# code. The DataLib portion also includes some automated unit tests.
The standard one-time price for the MigrationSupport source code is $5000. I would like to include this item on your price quote as an option so it can considered by your purchasing team along with the rest of our proposal. We should talk about your plans for finishing the migration so I can answer your questions about MigrationSupport and help you decide if you wish to purchase this optionWe are going to include this item on your price quote as an option. Please let me know when you can fit in a quick call on this.
Note, we have a "branding tool" that can rename code and files using the MigrationSupport namespace be consistent with your organization's naming standards.