修改config文件appsettings配置节中的add里的value属性=

#region 修改config文件appsettings配置节中的add里的value属性=

        /// <summary>

        /// 修改config文件appsettings配置节中的add里的value属性

        /// </summary>

        /// <remarks>

        /// 注意，调用该函数后，会使整个web application重启，导致当前所有的会话丢失

        /// </remarks>

        /// <param name="key">要修改的键key</param>

        /// <param name="strvalue">修改后的value</param>

        /// <exception cref="">找不到相关的键</exception>

        /// <exception cref="">权限不够，无法保存到web.config文件中</exception>

        public void Modify(string key, string strvalue)

        {

            string xpath = "/configuration/appSettings/add[@key='?']";

            XmlDocument domwebconfig = new XmlDocument();

            domwebconfig.Load(Server.MapPath("/config/contactus.config"));

            XmlNode addkey = domwebconfig.SelectSingleNode((xpath.Replace("?", key)));

            if (addkey == null)

            {

                throw new ArgumentException("没有找到<add key=" + key + " value=.../>的配置节");

            }

            addkey.Attributes["value"].InnerText = strvalue;

            domwebconfig.Save(Server.MapPath("/config/contactus.config"));

        }

        #endregion