If you download the C++ API, the HTML documentation (in the 'doc' directory - surf to index.html)
will tell you the objects which are accessible; the .Net wrapper classes could be expected to align
with them (tables and rows, with a geodatabase parent container and a number of geometry
accessor classes).
The FileGDB API uses the shapefile spec to transfer individual geometries in binary form, but there
is no support for shapefile access (read or write).
If you google 'shapefile specification' you'll find a number of links to the specification itself (which
is included in the FGBDAPI docs), plus the Wikipedia site (which has links to open-source shapefile
access APIs).
- V