ConfigurationSection Constructor

        // Create a custom section.
        static void CreateSection()
        {
            try
            {

                CustomSection customSection;

                // Get the current configuration file.
                System.Configuration.Configuration config =
                        ConfigurationManager.OpenExeConfiguration(
                        ConfigurationUserLevel.None);

                // Create the section entry  
                // in the <configSections> and the 
                // related target section in <configuration>.
                if (config.Sections["CustomSection"] == null)
                {
                    customSection = new CustomSection();
                    config.Sections.Add("CustomSection", customSection);
                    customSection.SectionInformation.ForceSave = true;
                    config.Save(ConfigurationSaveMode.Full);
                }
            }
            catch (ConfigurationErrorsException err)
            {
                Console.WriteLine(err.ToString());
            }

        }