Facebook’s query language (FQL) allows fetching results as $g(JSON) by supplying an additional “format=json” parameter as part of the request. I submitted a patch a few days ago that adds a UseJson property to the FQL object which was recently added to the Toolkit.
So, to fetch JSON results for FQL queries you can use the following:
facebook.fql q = new facebook.fql(Master.API); q.UseJson = true; string result = q.query("SELECT ...");
Be sure to grab the latest sources of the toolkit. Btw, the main reason for even mentioning it is that unless you’re reviewing the toolkit source code it’s unlikely you’d even know it’s there so this post will hopefully help people searching Google for the answer.
Take a look at this post to see how the JSON format can be useful for using Facebook data using an HttpHandler.