If you want to re-use your VFP app code in your web app without a total re-write, stick with the fox and just create a .vfp. mtdll to be called from ASP or ASP.NET. If you're ready to take the plunge and can afford the expense of rewriting in C# or VB, then go for it in .NET. The performance is not really going to be much different in either scenario.
From the VFP 8 FAQ page at http://msdn.microsoft.com/vfoxpro/productinfo/faq/default.aspx:
"Q. Can I use Visual FoxPro to build Web applications?
A. Visual FoxPro COM components can be used with Internet Information Services (IIS) to build high-powered Internet database applications. This is because Visual FoxPro components can be called from Active Server Pages (ASP). Visual FoxPro is compatible with ASP but works even better in conjunction with the more modern ASP.NET. The components will retrieve and manipulate data, and will build some of the HTML returned to the user.
Q. Why would I build a component in Visual FoxPro when I can build the same component in Microsoft Visual Basic or Microsoft Visual C++?
A. Visual FoxPro components are extremely fast, thanks to the data-centric language of Visual FoxPro and its ability to quickly retrieve and manipulate data. Further, Visual FoxPro can build character strings very swiftly. A Visual FoxPro component that works with data and returns HTML will, therefore, be very fast.
Visual FoxPro also has object-oriented programming capabilities, including inheritance. This provides a high degree of reuse across applications. A Visual FoxPro developer can create a set of classes that includes the core functionality of a Web database component, so that code will not need to be rewritten each time a component is needed in a Web application. The developer can simply create a component that inherits the base functionality, and then add application-specific code to it.
Finally, building COM components in Visual FoxPro is an excellent way to reuse existing code. Code that is already written and tested can be built into a component, rather than being recreated in another language.
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>our company is now in the process of rewriting our VFP7 application to use SQl as backend. We're thinking about a Web aplication since we have customers in USA and all around our country. We are taking some trainings of SQl sever too, we heard about N-tier app and we are wondering: is VFP8 the best for this kind of thing? is .Net? what do you guys think according to your experience?