Is there any VB6 to C# migration tool? [closed]

Answer 1

There are 2 free ones that I use:

http://www.carlosag.net/Tools/CodeTranslator/

http://www.developerfusion.co.uk/utilities/convertcsharptovb.aspx

Answer 2

As someone who has done this a bunch of times, this is not an easy process. You can use the VB6 to VB.Net tool as stated in this answer, and then use either Reflector or SharpDevelop to convert to C#. With the SharpDevelop conversion, a few caveats. It screws up all the array references and thinks that they are function calls, and all the logical operators are converted to bitwise logical operators (And becomes & not &&). With Reflector you lose a bunch of stuff. Also the Visual Studio converter fails on a lot of large projects, just hangs and never completes.

Once you have got your code converted into C#, you have to start the real work. The conversion gets you at best 50% of the way there, you have to fix a ton of stuff (you will see your code littered with TODO's), refactor a ton of stuff, and at the end you are left with C# that is a representation of your VB6 -- unless you have very nice VB6 code not a place you really want to be. Also all of your code with be littered with the VB helpers rather than using proper DotNet functions (all the string functions are helpers rather than class objects, for examples0. If you used Variants at all those all have to be rewritten. If you used a lot of API calls, they tend to need rewritting.

In the end you will get a base, but converting a large project (20-30 forms, 30 classes, 30 modules) can take several man months. Rewritting from scratch, however, may take twice as long and you lose all of your business logic. So, it can be done (I have done it with 3 or 4 large projects), but there is no panacea, no silver bullet, and any tool that says it will do it for you alone, is lying.

Answer 3

Microsoft recommends ArtinSoft’s Visual Basic Upgrade Companion (VBUC).

Microsoft and ArtinSoft have partnered to offer a free VBUC license to you. The discount code below can be used to purchase a license that will allow you to migrate an application of up to 10,000 lines of VB6 code to VB.NET or C# for free. It can also be applied when purchasing a larger license.

It's not perfect, resulting code still requires lots of manual fixes until it even compiles but still this tool is worth giving a shot.

Answer 4

At GreatMigrations, we do this by hand -- we use our hands to develop a VB6/COM compiler. The compiler reads a VBP (or group of related VBPs) and referenced COM libraries and constructs a "semantic model". This model is an extremely detailed set of symbol tables and opcode streams that fully and accurately describe all information structures defined and operations performed by the source system.

The tool then applies a series of algorithms that modify and restructure the model to make it more compatible with .NET and optionally applies custom transformations; for example to replace COM components with .NET classes. The transformation rules are designed by people and created "by hand" to meet their unique requirements.

Finally, the model is "executed" but instead of allocating the data model and executing the operations, we author the file structures, data model, and operations in the notation of the target platform. We can author both VB.NET and C# using this approach. We also use this process to migrate ASP sites to ASPX, (we also have a multi-dialect FORTRAN-to-C product)

The approach does not produce production ready software on the first try, but it can be improved and made to produce "better" software by modifying the configuration of the tool and re-running the translation process. The advantage of our tool is its repeatability, speed, and flexibility which facilitates an agile tool-assisted-rewrite methodology. IMO, migration teams that leverage our approach will benefit from allocating a lot more resources to evaluating alternatives for redesign, and development process improvements rather than to re-gathering functional requirements, hand coding, and testing. They will ultimately enjoy a more maintainable system and a much more faithful reproduction of the original application functionality after the migration as well as greater control and visibility during the migration.

A trial edition of our tool is available here gmStudio Trail Request Download. It will allow you to experiment with ASP/VB codes up to 10K LOC and runs for up to 30 sessions.