"git add ." in one command?

I write this code to simulate "git add ." :

        var r = new Repository("mydir");

        var status = r.RetrieveStatus();

        if (status.IsDirty)
        {
            foreach (var f in status.Untracked.Select(mods => mods.FilePath).ToList())
            {
                r.Index.Add(f);
            }

            foreach (var f in status.Modified.Select(mods => mods.FilePath).ToList())
            {
                r.Index.Add(f);
            }

            r.Index.Write();
        }

Is there a single instruction to do that? (something like : r.Add("."))

Start by reviewing the Repository, RetrieveStatus, Index.Add, and Index.Write calls shown in the issue, then search the repository for related indexing APIs. Done means providing or documenting one operation that matches the requested git add . behavior for the files described in the issue.