Applied biosystems DNA sequence format file contains a dna sequence in addition to a set of metadata associated with that sequence identify the chromatogram information that was used to determine that sequence residues.
 
http://www6.appliedbiosystems.com/support/software_community/ABIF_File_Format.pdf
 
There are a host of programs out there that work with this format and Applied Biosystems also has an xml converter to convert the binary format into an xml format. This could be used to parse these file types into a .Net class, however further parsing would need to be performed on individual metadata elements and it is extremely slow for a large number of files. Instead a custom binary parser would allow converting and manipulating the metadata / sequence with the bio framework at a much faster speed and easier to use format.