We are using RavenDB and generating IEnumerable (and have tried) IQueryable datasets which are added to the Flexcel report object with a .AddTable.
The datasets work okay but are blowing up when I try to filter using DISTINCT(Fieldname)
Is there a mechanism to debug what is wrong with the dataset, what is missing in the underlying classes, etc. - short of loading the sources and tracing the exceptions...
In the current stable version (5.7) Distinct isn't supported with IEumerable/IQueryable, because distinct is hard to use in a dynamic way. (Linq is targeted to static code, but we need to generate it on the fly).
Now, in FlexCel 6 this support was added, so your reports should work fine. There is nothing else that I can recall that should be missing form LINQ support, distinct was a special case and as said it was added.
We are targeting a release for v6 this week (having a lot of issues with the last xamarin tests, and everything is so slow when testing in phones). I am sorry v6 took that long, but well, there was a lot of code to be rewritten for going fully crossplat, and sadly also we needed to catch up with FlexCel for Delphi. After this is out of the door, releases should go back to a bimontly schedule I hope.
In any case, if you need this now (or if we miss the deadline and can't ship v6 this week), please email me to adrian@tmssoftware.com and I'll send you a link to the latest version available, I think 5.9.14, which has this "distinct" support. (It was added in jan 2013)