动态修改微软企业库的连接字符串

微软企业库，可以连接不同的数据库。
Database db = DatabaseFactory.CreateDatabase();
运行时，会根据用户配置的不同，而创建不同的数据库实例。如果能够在程序运行后，动态修改数据库的连接字符串呢？本文提供了笔者的一种动态修改软企业库连接字符串的方法

       /// <summary>
        /// 读取数据库默认连接字符串
        /// </summary>
        /// <returns></returns>
        private string ReadDefaultConnectString()
        {
            Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            ConfigurationSection dataConfigurationSection = config.Sections["dataConfiguration"];
            string defaultDatabase = (dataConfigurationSection as Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings).DefaultDatabase;

            ConfigurationSection connectionConfigurationSection = config.Sections["connectionStrings"];
            ConnectionStringsSection connectionStringsSection = connectionConfigurationSection as ConnectionStringsSection;
            return connectionStringsSection.ConnectionStrings[defaultDatabase].ConnectionString;
        }

        /// <summary>
        /// 保存数据库默认连接字符串
        /// </summary>
        /// <param name="connectString"></param>
        private void SaveDefaultConnectString(string connectString)
        {
            Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            ConfigurationSection dataConfigurationSection = config.Sections["dataConfiguration"];
            string defaultDatabase = (dataConfigurationSection as Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings).DefaultDatabase;

            ConfigurationSection connectionConfigurationSection = config.Sections["connectionStrings"];
            ConnectionStringsSection connectionStringsSection = connectionConfigurationSection as ConnectionStringsSection;
            connectionStringsSection.ConnectionStrings[defaultDatabase].ConnectionString = connectString;
            config.Save();
        }

        /// <summary>
        /// 刷新数据库默认连接字符串
        /// </summary>
        private void RefreshConfig()
        {
            ConfigurationManager.RefreshSection("dataConfiguration");
            ConfigurationManager.RefreshSection("connectionStrings");
        }