Migrating Visual Basic Applications?

goose69 asks: "I was looking at the various options available to migrate Visual Basic applications on to GNU/Linux , as usual the choices were many from Free Solutions like wxWindows, Gambas, vb2py, to proprietary ones like Phoenix, and so on. Unfortunately, Mono was too much with its multiple licenses. I want to know if anyone out there has done a successful migrations from Visual Basic on Windows to any application framework on GNU/Linux."

Comments

Problem with the licencing?????

[TsEA]

Excuse me, but I really can't understand the phrase: "Unfortunately, Mono was too much with its multiple licenses."
Anybody read this? http://www.mono-project.com/FAQ:_Licensing
Uses 3 common licences from the GNU/Linux world, GPL, LGPL and MIT/X11. Don't you use X? Don't you use the linux kernel? Does the licensing trouble you?
I really didn't understand this, Mono is one of the clearest (and most convienient) in licensing terms....

COM and other considerations

[Joey Vegetables]

A lot of VB code is mostly glue tying together COM components, such as UI elements, database libraries (ODBC/OLEDB), etc..

There is nothing exactly like COM in the Linux/UNIX world, although large projects such as KDE, Gnome, and Mozilla do have rough equivalents if you are willing to rely on them for part of your functionality. Also, much of what Linux lacks in terms of COM is more than compensated by the existence of rich CLI tools that are designed to be tied together with a "glue" language such as shell, Python, Perl, etc.

My approach has generally been to enforce separation between data, business logic, and presentation to the greatest extent possible. This way, any component can be replaced or migrated to another dev tool or platform if needed.

Postgres is a great back-end database, and the only Free one I can recommend for most serious apps. Middle-tier / business logic components can be written in pretty much any language that can communicate with both the database and the front end. I like to prototype in Python and then possibly port to C++ later when/if there's a need.

The front end is the biggest challenge. The Qt and wxWidgets libraries are extremely well regarded and mature, and there are form builder utilities for both, which approximate (but IMO don't exactly equal) the ease of the Windows forms designers. For reporting, numerous PDF generation tools exist although I don't have a lot of experience with any of them, and most will not have the "drag and drop" interface you may be used to from Crystal or Access, but once you get used to writing code that generates output, I find it's a lot more productive than "drag and drop" anyway.

Most VB code isn't particularly object-oriented (especially since until .NET, VB did not support implementation inheritance). As such, a good multiparadigm language like Python, which supports but does not require OOP, seems like a very good choice.

Packaging will be an issue. Not all of your target users will have identical operating systems, libraries, or locations for common files. You will need to use some combination of Ant, Make, Autoconf, and similar tools in order to distribute your software in such a way that it can be easily compiled and installed by end users (if appropriate) or whomever else your target market may be.

Good luck!

Re:You may not like it, but....

[ikilledmidnight]

I personally prefer RB over VB for a number of reasons, including:

• unlike VB you don't have to have certain DLLs installed etc, the apps are self contained
• It's cross platform from the same code (Windows 98 and onwards), OS 9, OS X, Linux (Redhat SuSE, I dunno about any others)
• I find the IDE, far more intuitive and less cluttered and not so 'Windows 95'
• The help system is FAR better
• theres way more default controls, for example theres a TCP socket in RB you don't have to import the winsock dll to add TCP capabilities

to be fair I haven't used VB since VB 6, so I have no idea what .net is like, but thats the way I see things anyway...

Java

[Mr. Shiny And New]

You could always consider Java. Java has lots of support in the Open Source world. The Eclipse IDE is pretty nice. JBuilder, while not Free, has a decent GUI editor (never looked for one for Eclipse, so I don't know if it has one) that can approximate the drag-and-drop approach of VB. Java can do pretty much anything you need it to do, and it's cross-platform. Performace with a modern VM is not a problem.
The only real problem Java has is that there is no good Free JVM. But I expect that will change in the future. But in the meantime, the Sun JVM is available for most interesting platforms. Java code is pretty easy to write, and maintain, it's well understood by lots of people, it's proven to work well on large workloads, and it has good open-source and proprietary support.

Mono is the obvious choice

[aCapitalist]

But the compiler being GPL, the runtime being LGPL, and the libraries being MIT/X11 are too much for this guy too handle.

Seriously, they're an MS shop who is used to using Visual Studio. The most natural, non-painful migration is to write code using C# and Gtk# or possibly winforms (depending on the maturity of Mono's effort) in Visual Studio on Windows and just copy the binaries or re-compile on Unix until such time that MonoDevelop or some other IDE is mature enough to use.

These are VB guys we're talking about. They're just going to laugh at you if you throw them in front of a Unix workstation and tell them to fire up Emacs or Vim.