DirectoryInfo myInfo = new DirectoryInfo(DbFolderPath); FileInfo[] myDbFiles = myInfo.GetFiles("*.db", SearchOption.TopDirectoryOnly); string myFileName; foreach (FileInfo item in myDbFiles) { myFileName = Path.GetFileNameWithoutExtension(item.Name); if (int.TryParse(myFileName, out int myDummy)) { Result.Add(item.FullName); } }