I have a project coming up where I would have to design a form for clients to be able to "map" one data structure to another.

The idea is to have two windows on a form (kinda like a mover "look") where the right-hand side is the resulting data format (known, fixed and actually XML). The left-hand side, is empty and variable. It would depend on each company's internal data structure and the purpose is for them to be able to map their proprietary internal structures to a new XML format I'm creating. This will replace a flat file currently in use.

As they currently produce a flat file, they know their data. This tool is for them to be able to tell us, where in their internal data structures do we find each field to run a "converter" tool I'm designing (in VFP8). This way they would not need to learn how to do XML (consider that they may have non-Windows hosts, like unix, minis or even mainframes in some cases). They would just simply tell our tool how to convert their existing flat file to XML.

The question here is what controls (native VFP8, ActiveX or whatever) are best suited for this.

I remember seeing a similar interface in the old BizTalk software, but it's been a long time and I don't have it handy. I remember it had a way to graphically show intersecting lines connecting the two halves, whenever you drag and drop one left-side field into it's right-hand side equivalent and that looked good.

Has anybody done something like that?

I hope the explanation is clear enough.