/// <summary>
        /// Return list of all donors whose codes are
        /// in our file list.
        /// </summary>
        /// <returns></returns>
        public List <Donor> DonorsInFileList()
        {
            List <Donor> retList = new List <Donor>();
            // For each file, if it's of the proper type,
            // (ie if it's not a type for which donor
            // is irrelevant), add its donor to our
            // return list.
            List <string> codes = new List <string>();

            foreach (HllFileInfo hfi in RegularHllFiles)
            {
                if (hfi.HasDonor)
                {
                    codes.Add(hfi.DonorCode);
                }
            }
            // remove dupes:
            codes = codes.Distinct().ToList();
            // Now add donors to our retList, using the codes we found:
            foreach (string c in codes)
            {
                Donor d = context.FindDonorByCode(c);
                if (d == null) // Uh-oh! This is a new donor.
                {
                    // add it to datastore as well as to our return list
                    d = new Donor(c, c);
                    context.AddOrUpdateDonor(d);
                }
                retList.Add(d);
            }
            // Sort the list by donor name:
            return(retList.OrderBy(d => d.name).Distinct().ToList());
        }