public IActionResult CsvExport()
        {
            var allMembers = _parteiDbContext.Members.ToList();

            CSVExportManager.CreateMemberCSV(CSVExportManager.MapMemberToModelMember(allMembers), "wwwroot/export/export.csv");

            var net         = new System.Net.WebClient();
            var data        = net.DownloadData("wwwroot/export/export.csv");
            var content     = new System.IO.MemoryStream(data);
            var contentType = "application/vnd.ms-excel";
            var fileName    = "export.csv";

            return(File(content, contentType, fileName));
        }
        public async Task <IActionResult> CsvImport(IFormFile file)
        {
            int organisationId = 2; // TODO hier noch die Anpassung machen!!!


            if (file == null)
            {
                throw new FileNotFoundException("Fehler beim einlesen der CSV-Datei.");
            }
            if (!Path.GetExtension(file.FileName).EndsWith(".csv"))
            {
                throw new FileNotFoundException("Es handelt sich nicht um eine CSV-Datei.");
            }

            var fileName = System.IO.Path.GetFileName(file.FileName);
            var path     = "wwwroot/export/" + fileName;

            if (System.IO.File.Exists(path))
            {
                System.IO.File.Delete(path);
            }

            using (var localFile = System.IO.File.OpenWrite(path))
                using (var uploadedFile = file.OpenReadStream())
                {
                    uploadedFile.CopyTo(localFile);
                }

            foreach (var modelMember in CSVExportManager.ReadMemberCSV(path).Users)
            {
                _parteiDbContext.Add(CSVExportManager.MapModelMemberToMember(modelMember, Guid.NewGuid().ToString(), organisationId));
            }
            _parteiDbContext.SaveChanges();

            System.IO.File.Delete(path);

            var allMembers = _parteiDbContext.Members.ToList();

            return(RedirectToAction("Index"));
        }