autocad block attribute extraction lib

We need a library in dot net that can extract block attributes out of autocad drawings. ## Deliverables We need a library in dot net that can extract block attributes out of autocad drawings. The library should implement a function that takes a file-handle and returns all the found blocks and their tags. Besides the library, there should also be a simple app that tests the lib functionality. The library should not write and read temporary files. We should be able to freely distribute the library and everything it needs (so dependency on the autocad application is not an option).