sharplibzip: supplement record but path

i'm controlling following code, controlling library, supplement files .zip file, nonetheless any record being stored the full path. i need wholly store file, 'root' .zip file.

string[] files = directory.getfiles(folderpath);
using (zipfile zipfile = zipfile.create(zipfilepath))
{
     zipfile.beginupdate();
     foreach (string record files)
     {
          zipfile.add(file);
     }
     zipfile.commitupdate();
}

i can't anything an choice reputed documentation. unequivocally renouned library, i wish someone reading competence know something.