Configuration configuration = WebConfigurationManager.OpenWebConfiguration("~");
ConfigurationSection configurationSection = configuration.GetSection("connectionStrings");
configurationSection.SectionInformation.ProtectSection("DataProtectionConfigurationProvider");
configurationSection.SectionInformation.ForceSave = true;
configuration.Save(ConfigurationSaveMode.Full);

Response.Write ( ConfigurationManager.ConnectionStrings["MinhaConnectionString"].ConnectionString );