VB 6 to VB.NET Migration Proceeds Ever So Slowly

Posted by Jonathan Allen on Feb 22, 2008

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Six years after VB.NET was released, Microsoft is still slowly working towards a true migration path for VB 6 applications. Recently Microsoft released "Visual Basic Power Packs 3.0". This release adds the Data Repeater, an important control for layouts.

The Data Repeater is based on the VB 6 layout control. It takes a set of controls and replicates them for each row in a data source. The controls can be laid out horizontally or vertically and support scrolling.

Also included in this release are the Lines and Shapes controls and the VB 6 style Printer Library from previous releases. All three include a bootstrapper package making it easier to include them in ClickOnce and MSI based deployments.

While this would certainly be useful for developers who are just now starting their conversion process, one has to wonder if there are any VB 6 applications left that will be converted. By now most companies have probably either made the conversion or resigned themselves to starting a new version from scratch.

The Power Pack is available from Microsoft's Download Center.

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   re: one has to wonder if there are any VB 6 applications left ...

   by mark juras

   Many large corporate and commercial VB6 (not to mention ASP) applications contain dozens of person-years of development effort. Many organizations that run/sell these huge applications are still maintaining them in VB6 (yes, the person-years of development continue to pile on). And, they are all struggling with how to upgrade these applications in an efficient, effective manner that does not completely overwhelm their labor supply. Just "starting a new version scratch" is simply not feasible, for it would mean re-doing dozens of person-years of work on top of everything else.... High-yield custom tool-assisted rewrite (i.e., a custom translation) may be the only feasible approach -- assuming they can agree on what their applications should look like in .NET.

   Reply

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   Interop Forms Toolkit

   by Rob Windsor

   First off, there is a ton of VB 6.0 code out there and there's more being developed every day.
   
   The most important tool the VB Team has released to assist people supporting this legacy code base is the Interop Forms Toolkit. The toolkit allows developers to easily create forms and user controls in .NET which can be used in VB 6.0 client applications.
   
   This Channel 9 video gives a good introduction:
   
   channel9.msdn.com/Showpost.aspx?postid=327369

   Reply

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   Re: re: one has to wonder if there are any VB 6 applications left ...

   by Rob Windsor

   The best strategy is a phased migration with COM Interop. This allows companies to begin to rewrite obsolete or high maintenance code using .NET while leaving the remiaining legacy code in place. A full-scale migration or rewrite is risky and time consuming as well as expensive. Using the phased approach, each "piece" of the migration is low-risk and gives almost immediate value.
   
   I did an interview on .NET Rocks TV on this subject which you can check out here:
   
   www.dnrtv.com/default.aspx?showNum=94

   Reply

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   Migration

   by RaviKiran Belthur

   The most important thing with the migration is to have the VB6 code prepared correctly so that it will be ready for migration.
   We need more and more customized tool which can provide rule based migration stratergies.

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   Re: Migration

   by Jerry Caussade

   COM Interop is a VERY short-term solution. Microsoft has dropped support for the VB6 IDE. You can't rely on the Upgrade Wizard, but the same company that developed that, ArtinSoft, has an enterprise version called the VBUC. It migrates to C# as well, and large banks have migrated millions of lines of code succcessfully with it. It is MUCH better than the Wizard. It is low risk and takes about 1/4 to 1/3 the time of a manual rewrite to fully complete a migration and test it.
   
   I agree a manual rewrite is very risky.
   I do think that Form Interop with the VBUC is an interesting combinationt, though. If your VB6 code is modular enough, you can migrate parts of the code and have it temporarily run in the VB6 environment. But check out ArtinSoft's VBUC tool. It even handles Variants (if not late-bound).

   Reply