How to query form library in SharePoint 2010?

In MOSS 2007 we use a CAML query to query the SharePoint list and in SharePoint 2010 I found the newly introduced LINQ to SharePoint (where using SPMetal utility we generate a data context class) which 开发者_运维问答works fine for a SharePoint list but how do I query a form library were most of the fields are promoted to it from the Infopath form?

I would suggest use LINQ To XML