public List <string> GetDomainControllers()
        {
            List <string> DcList = new List <string>();

            using (DirectorySearcher Searcher = new DirectorySearcher(new DirectoryEntry()))
            {
                Searcher.Filter = "(primaryGroupID=516)";
                foreach (SearchResult DC in Searcher.FindAll())
                {
                    DcList.Add(DC.GetDirectoryEntry().Name.Remove(0, 3));
                }
            }
            return(DcList);
        }