Saving Connection Strings to app.config

/// <summary>
/// Adds a connection string settings entry & saves it to the associated config file.
///
/// This may be app.config, or an auxiliary file that app.config points to or some
/// other xml file.
/// ConnectionStringSettings is the confusing type name of one entry including: 
/// name + connection string + provider entry
/// </summary>
/// <param name="configuration">Pass in ConfigurationManager.OpenMachineConfiguration, 
/// ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None) etc. </param>
/// <param name="connectionStringSettings">The entry to add</param>

public static void AddAndSaveOneConnectionStringSettings(
       System.Configuration.Configuration configuration,
       System.Configuration.ConnectionStringSettings connectionStringSettings)
{
      // You cannot add to ConfigurationManager.ConnectionStrings using
      // ConfigurationManager.ConnectionStrings.Add(connectionStringSettings) -- This fails.
 
      // But you can add to the configuration section and refresh the ConfigurationManager.
 
      // Get the connection strings section; Even if it is in another file.
      ConnectionStringsSection connectionStringsSection = configuration.ConnectionStrings;
 
      // Add the new element to the section.
      connectionStringsSection.ConnectionStrings.Add(connectionStringSettings);
 
      // Save the configuration file.
      configuration.Save(ConfigurationSaveMode.Minimal);
 
      // This is this needed. Otherwise the connection string does not show up in
      // ConfigurationManager
      ConfigurationManager.RefreshSection("connectionStrings");
}