public static void CreateAppSettings(){  // Get the application configuration file.  System.Configuration.Configuration config =    ConfigurationManager.OpenExeConfiguration(          ConfigurationUserLevel.None);  string sectionName = "appSettings";  // Add an entry to appSettings.  int appStgCnt =      ConfigurationManager.AppSettings.Count;  string newKey = "NewKey" + appStgCnt.ToString();  string newValue = DateTime.Now.ToLongDateString() +     " " + DateTime.Now.ToLongTimeString();  config.AppSettings.Settings.Add(newKey, newValue);  // Save the configuration file.  config.Save(ConfigurationSaveMode.Modified);  // Force a reload of the changed section. This   // makes the new values available for reading.  ConfigurationManager.RefreshSection(sectionName);  // Get the AppSettings section.  AppSettingsSection appSettingSection =    (AppSettingsSection)config.GetSection(sectionName);  Console.WriteLine();  Console.WriteLine("Using GetSection(string).");  Console.WriteLine("AppSettings section:");  Console.WriteLine(    appSettingSection.SectionInformation.GetRawXml());}