Best way to convert XML to X12 and X12 to XML

I ended up creating my own XML <-> x12 transformation tool. There were some commercial offerings that I came across (one of which, from EtaSoft, is worth checking out for their fine documentation) but ultimately the advantage of a homegrown solution was too great.

I did use the configuration files from X12::Parser as the basis for an X12 parser, essentially turning the config file into code and eliminating the overhead and error handling for managing configuration files that should in theory almost never change.

I came across this: OopFactory X12 Parser - https://x12parser.codeplex.com/releases/view/106524

Incredible. Source code was well structured, everything built on first open, even had unit tests.

Pulled into my project, it converted all the files I tried.

It includes a command line exe which worked - but as a .Net guy the library was really impressive.

-Update-

The short short version comes down to something like this:

var fstream = new FileStream(fileName, FileMode.Open, FileAccess.Read);
var parser = new X12Parser();
var interchange = parser.ParseMultiple(fstream).First();
var x12Xml = interchange.Serialize();

One product I can speak to that you should avoid at all costs is EcMap. Having had about a year of experience with it now in my own employment in an EDI department, I can say I have seldom seen an application with a more poorly designed interface (except perhaps Lotus Notes), more confusing user documentation, and an absolutely ridiculous licensing scheme. It's essentially licensed per CPU (by CPU they mean core, so you're really hosed if you've got a new quad-core CPU) and it's more than 10K per license by the last quote I heard.