本文共 3923 字，大约阅读时间需要 13 分钟。

转自：http://www.cnblogs.com/wangsu/archive/2008/02/25/1081226.html

public class ConfigureAppConfig    {        //静态构造,不能实例化        static ConfigureAppConfig() { }        /// 
        /// 获取AppSettings配置节中的Key值        /// 
        /// Key's name        /// 
   
    Key's value
           public static string GetAppSettingsKeyValue(string keyName)        {            return ConfigurationManager.AppSettings.Get(keyName);        }        /// 
        /// 获取ConnectionStrings配置节中的值        /// 
        /// 
           public static string GetConnectionStringsElementValue()        {            ConnectionStringSettings settings = System.Configuration.ConfigurationManager.ConnectionStrings["connectionString"];            return settings.ConnectionString;        }        /// 
        /// 保存节点中ConnectionStrings的子节点配置项的值        /// 
        ///         public static void ConnectionStringsSave(string ConnectionStringsName, string elementValue)        {            System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);            config.ConnectionStrings.ConnectionStrings["connectionString"].ConnectionString = elementValue;            config.Save(ConfigurationSaveMode.Modified);            ConfigurationManager.RefreshSection("connectionStrings");        }        /// 
        /// 判断appSettings中是否有此项        /// 
        private static bool AppSettingsKeyExists(string strKey, Configuration config)        {            foreach (string str in config.AppSettings.Settings.AllKeys)            {                if (str == strKey)                {                    return true;                }            }            return false;        }        /// 
        /// 保存appSettings中某key的value值        /// 
        /// key's name        /// value        public static void AppSettingsSave(string strKey, string newValue)        {            System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);            if (AppSettingsKeyExists(strKey, config))            {                config.AppSettings.Settings[strKey].Value = newValue;                config.Save(ConfigurationSaveMode.Modified);                ConfigurationManager.RefreshSection("appSettings");            }        }    }

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另外，也可用：

public class AppSettings    {        public static string AppConfig()        {            return System.IO.Path.Combine(Application.StartupPath, "xxx.exe.config");        }        public static string GetValue(string appKey)        {            XmlDocument xDoc = new XmlDocument();            try            {                xDoc.Load(AppSettings.AppConfig());                XmlNode xNode = xDoc.SelectSingleNode("//appSettings");                XmlElement xElem = (XmlElement)xNode.SelectSingleNode("//add[@key='" + appKey + "']");                               if (xElem != null)                    return xElem.GetAttribute("value");                else                    return "";            }            catch             {                return "";            }        }        public static void SetValue(string AppKey, string AppValue)        {            XmlDocument xDoc = new XmlDocument();            xDoc.Load(AppSettings.AppConfig());            XmlNode xNode = xDoc.SelectSingleNode("//appSettings");            XmlElement xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@key='" + AppKey + "']");                                        if (xElem1 != null)            {                xElem1.SetAttribute("value", AppValue);            }            else            {                XmlElement xElem2 = xDoc.CreateElement("add");                xElem2.SetAttribute("key", AppKey);                xElem2.SetAttribute("value", AppValue);                xNode.AppendChild(xElem2);            }            xDoc.Save(AppSettings.AppConfig());        }    }