public static void Main(string[] args) { try { // Open the default app.config file which in this case is SimpleExample.exe.config // and it is located in the same folder as the SimpleExample.exe. settings = AppSettings.CreateForAssembly(Assembly.GetEntryAssembly(), FileOption.FileMustExist); // Write all the settings into our own object var mySettings = new MyApplicationSettings(); settings.WriteInto(mySettings); mySettings.StringValue = new string(mySettings.StringValue.Reverse().ToArray()); // Read everything back into settings and save settings.ReadFrom(mySettings); settings.Save(); } catch (Exception exp) { Console.Error.WriteLine(exp.Message); throw; } }