Winform代码里修改App.config中值

 public class AppConfig
    {
        /// <summary>
        /// 修改AppConfig值
        /// </summary>
        private XmlDocument Doc = new XmlDocument();
        private AppDomain Ad = AppDomain.CurrentDomain;
        public AppConfig()
        {
            Doc.Load(Ad.SetupInformation.ConfigurationFile);
        }
        public void LoadAppConfig()
        {
            Doc.Load(Ad.SetupInformation.ConfigurationFile);
        }
        public void SetAppValue(string key, string newValue)
        {
            Doc.SelectSingleNode("/configuration/appSettings/add[@key='" + key + "']").Attributes["value"].Value = newValue;
        }
        public void SaveAppConfig()
        {
            Doc.Save(Ad.SetupInformation.ConfigurationFile);
            Doc.Load(Ad.SetupInformation.ConfigurationFile);
        }
        public string GetAppValue(string key)
        {
            return Doc.SelectSingleNode("/configuration/appSettings/add[@key='" + key + "']").Attributes["value"].Value;
        }
    }

直接调用 SetAppValue(string key,string newValue);

再加上一句SaveAppConfig();