But first a bit of background. Prior to July 18, 2012, if anyone had told me you could base a value list on an unstored field, my response would have been something along the lines of…
- What app are you using? (Because it sure as heck ain’t FileMaker.)
- Why are you wasting my time with this nonsense?
- Is today April Fool’s Day?
- What are you smoking?
But then John Ahn showed this amazing Conditional Value List demo during the DevCon “Unconference” session devoted to ExecuteSQL (see previous posting), and to my way of thinking, the most intriguing part of session was only incidentally concerned with SQL, because John seemingly had achieved the impossible — a value list based on an unstored field.
Here’s a value list definition from John’s demo:
And here’s the field the value list is based on:
So it turns out that it isn’t “impossible” after all, and since I was at DevCon I took the opportunity to ask one of the FileMaker engineers about this behavior, and he assured me that while the behavior is undocumented, it “works as expected” and is not likely to go away any time soon.
And since Andries was in the audience during the session, and since he had a long flight home to Belgium a few days later, he was able to put together the MagicValueList demo, and suggested that FileMakerHacks might be a good place to showcase it.
Andries has done a superb job of explaining the intricacies of this technique, so really there isn’t much else for me to say except thank you to both Andries for the demo, and to John Ahn for the revelation that what most of us thought was impossible… isn’t.