修改web.config,app.config

1,修改web.config

Configuration config = WebConfigurationManager.OpenWebConfiguration("~");
config.AppSettings.Settings["a1"].Value = "new value";
config.Save(ConfigurationSaveMode.Modified);

2，修改app.config

Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
config.AppSettings.Settings["a1"].Value = "new value";
config.Save(ConfigurationSaveMode.Modified);