VB6 to .NET Migration: Decision and Analysis

Recently completed a huge project migrated a fairly decent size code base from Visual Basic 6 (VB6) to C# .NET. Yes, I said “migrated”, not rewrite – let’s get that out of the way up front. The code was migrated.

How did we go about doing this? Well, I’d like to detail it out over a few posts here and in the near future.

First, you need to make the decision to migrate instead of rewrite. Not very often do dev shops get the chance to do a rewrite, and even when they do, most rewrites go over time and budget and end up losing business logic and functionality, that is why the decision to migrate instead of rewrite is a such a good one.

So, after making that decision, which hopefully you do early, or before you are in the middle of a rewrite (as we did), you can get started. There are a few options, and I won’t go into complete detail on them, but just go over them high level..

1. Use the Visual Studio Migration tool and convert the code yourself and go at it alone

2. Look at the various companies out there that do migrations and pick one, and create a project that way.

We went with #2. After some research it was pretty obvious who the main player was out there, ArtInSoft. After researching them and watching their webcasts and reading and doing as much looking into as we could, we contacted them.

Their model is pretty simple, they send someone out to you for a week (on your dime) and they analyze the VB6 project to see how much it would take to migrate.

What I learned shortly after talking with ArtInSoft and bringing one of their analysts here is that ArtInSoft actually created the VB6->.NET conversion wizard in Visual Studio. What it is, is a lightweight version of the VBUC (Visual Basic Upgrade Companion) that they licensed to Microsoft. The VBUC in Visual Studio is very limited though. It will only migrate to VB.NET and has many other limitations, but it does still work. If you had a very small project (lines of code, complexity) – you could easily use the VBUC in Visual Studio, but most projects aren’t simple and have many lines of code, that is where you would want to use ArtInSoft and their “enterprise” version of the VBUC, as well as assistance from ArtInSoft.

Back to analysis. What they do is actually migrate your project, find any ancillary projects you might have and make sure everything gets converted. Their VBUC puts in EWI’s, Errors, Warnings and Issues, within comments in the newly converted code.

They then go throw the code and do find’s on all the EWI’s, dump them and parse them out, put into excel and pivot them to analyze how many of each EWI you might have. That way they can estimate how much effort/time/money it might be to do your project. They have done this many times, so they have it pretty much down to a science.

An example would be, you have 2500 warnings for warning XYZ – we know it takes 2 minutes to fix one of those, and they are usually all unique, so then we know the total time it would take to resolve them all.

After doing their analysis, they give you a project estimation, and then it is up to you to decide if you want to move forward, and when you would want to move forward..

 

To Be Continued…

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