public class ConfigUtils    {        public static string filename = System.Windows.Forms.Application.StartupPath + @"\App.config";        /// 
        /// 对[appSettings]节点依据Key值读取到Value值，返回字符串        /// 
        /// 要读取的Key值        /// 
     
      返回Value值的字符串
             public static string GetAppSetting(string key)        {            string value = null;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//appSettings");             XmlElement element = (XmlElement)node.SelectSingleNode("//add[@key='" + key + "']");            if (element != null)            {                value = element.GetAttribute("value");            }            return value;        }        /// 
        /// 对[connectionStrings]节点依据name值读取到connectionString值，返回字符串        /// 
        /// 要读取的name值        /// 
     
      返回connectionString值的字符串
             public static string GetConnectionString(string name)        {            string connectionString = null;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//connectionStrings");             XmlElement element = (XmlElement)node.SelectSingleNode("//add[@name='" + name + "']");            if (element != null)            {                connectionString = element.GetAttribute("connectionString");            }            return connectionString;        }        /// 
        /// 更新或新增[appSettings]节点的子节点值，存在则更新子节点Value,不存在则新增子节点，返回成功与否布尔值        /// 
        /// 子节点Key值        /// 子节点value值        /// 
     
      返回成功与否布尔值
             public static bool SetAppSetting(string key, string value)        {            bool isSuccess = false;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//appSettings");            try            {                if (node == null)                {                    //不存在则新增appSettings子节点                    XmlNode root = doc.DocumentElement;                    XmlElement appElement = doc.CreateElement("appSettings");                    XmlElement subElement = doc.CreateElement("add");                    subElement.SetAttribute("key", key);                    subElement.SetAttribute("value", value);                    appElement.AppendChild(subElement);                    root.AppendChild(appElement);                }                else                {                    XmlElement element = (XmlElement)node.SelectSingleNode("//add[@key='" + key + "']");                    if (element != null)                    {                        //存在则更新子节点Value                        element.SetAttribute("value", value);                    }                    else                    {                        //不存在则新增子节点                        XmlElement subElement = doc.CreateElement("add");                        subElement.SetAttribute("key", key);                        subElement.SetAttribute("value", value);                        node.AppendChild(subElement);                    }                }                using (XmlTextWriter xmlwriter = new XmlTextWriter(filename, null))                {                    xmlwriter.Formatting = Formatting.Indented;                    doc.WriteTo(xmlwriter);                    xmlwriter.Flush();                }                isSuccess = true;            }            catch (Exception e)            {                isSuccess = false;            }            return isSuccess;        }        /// 
        /// 更新或新增[connectionStrings]节点的子节点值，存在则更新子节点,不存在则新增子节点，返回成功与否布尔值        /// 
        /// 子节点name值        /// 子节点connectionString值        /// 子节点providerName值        /// 
     
      返回成功与否布尔值
             public static bool SetConnectionString(string name, string connectionString, string providerName)        {            bool isSuccess = false;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//connectionStrings");             try            {                if (node == null)                {                    //不存在则新增connectionStrings子节点                    XmlNode root = doc.DocumentElement;                    XmlElement connElement = doc.CreateElement("connectionStrings");                    XmlElement subElement = doc.CreateElement("add");                    subElement.SetAttribute("name", name);                    subElement.SetAttribute("connectionString", connectionString);                    subElement.SetAttribute("providerName", providerName);                    connElement.AppendChild(subElement);                    root.AppendChild(connElement);                }                else                {                    XmlElement element = (XmlElement)node.SelectSingleNode("//add[@name='" + name + "']");                    if (element != null)                    {                        //存在则更新子节点                        element.SetAttribute("connectionString", connectionString);                        element.SetAttribute("providerName", providerName);                    }                    else                    {                        //不存在则新增子节点                        XmlElement subElement = doc.CreateElement("add");                        subElement.SetAttribute("name", name);                        subElement.SetAttribute("connectionString", connectionString);                        subElement.SetAttribute("providerName", providerName);                        node.AppendChild(subElement);                    }                }                doc.Save(filename);                isSuccess = true;            }            catch (Exception e)            {                isSuccess = false;            }            return isSuccess;        }        /// 
        /// 更新或新增[connectionStrings]节点的子节点值，存在则更新子节点,不存在则新增子节点，返回成功与否布尔值        /// 
        /// 子节点name值        /// 子节点connectionString值        /// 子节点providerName值        /// 
     
      返回成功与否布尔值
             public static bool SetConnectionString(string name, string connectionString)        {            bool isSuccess = false;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//connectionStrings");             try            {                if (node == null)                {                    //不存在则新增connectionStrings子节点                    XmlNode root = doc.DocumentElement;                    XmlElement connElement = doc.CreateElement("connectionStrings");                    XmlElement subElement = doc.CreateElement("add");                    subElement.SetAttribute("name", name);                    subElement.SetAttribute("connectionString", connectionString);                    connElement.AppendChild(subElement);                    root.AppendChild(connElement);                }                else                {                    XmlElement element = (XmlElement)node.SelectSingleNode("//add[@name='" + name + "']");                    if (element != null)                    {                        //存在则更新子节点                        element.SetAttribute("connectionString", connectionString);                    }                    else                    {                        //不存在则新增子节点                        XmlElement subElement = doc.CreateElement("add");                        subElement.SetAttribute("name", name);                        subElement.SetAttribute("connectionString", connectionString);                        node.AppendChild(subElement);                    }                }                doc.Save(filename);                isSuccess = true;            }            catch (Exception e)            {                isSuccess = false;            }            return isSuccess;        }        /// 
        /// 删除[appSettings]节点中包含Key值的子节点，返回成功与否布尔值        /// 
        /// 要删除的子节点Key值        /// 
     
      返回成功与否布尔值
             public static bool DeleteAppSetting(string key)        {            bool isSuccess = false;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//appSettings");             XmlElement element = (XmlElement)node.SelectSingleNode("//add[@key='" + key + "']");            if (element != null)            {                //存在则删除子节点                element.ParentNode.RemoveChild(element);            }            try            {                using (XmlTextWriter xmlwriter = new XmlTextWriter(filename, null))                {                    xmlwriter.Formatting = Formatting.Indented;                    doc.WriteTo(xmlwriter);                    xmlwriter.Flush();                }                isSuccess = true;            }            catch (Exception e)            {                isSuccess = false;            }            return isSuccess;        }        /// 
        /// 删除[connectionStrings]节点中包含name值的子节点，返回成功与否布尔值        /// 
        /// 要删除的子节点name值        /// 
     
      返回成功与否布尔值
             public static bool DeleteConnectionString(string name)        {            bool isSuccess = false;            XmlDocument doc = new XmlDocument();            doc.Load(filename);             XmlNode node = doc.SelectSingleNode("//connectionStrings");             XmlElement element = (XmlElement)node.SelectSingleNode("//add[@name='" + name + "']");            if (element != null)            {                //存在则删除子节点                node.RemoveChild(element);            }            try            {                doc.Save(filename);                isSuccess = true;            }            catch (Exception e)            {                isSuccess = false;            }            return isSuccess;        }    }

 

class SetConfig    {        /// 
        /// 对[appSettings]节点依据Key值读取到Value值        /// 
        ///         /// 
             public static string GetAppSettings(string strKey)        {            foreach (string key in ConfigurationManager.AppSettings)            {                if (key == strKey)                {                    return ConfigurationManager.AppSettings[strKey];                }            }            return null;        }        /// 
        /// 更新或新增[appSettings]节点的子节点值        /// 
        ///         ///         public static void SetAppSettings(string newKey, string newValue)        {            bool isModified = false;            // 如果要更改的Key已经存在            foreach (string key in ConfigurationManager.AppSettings)            {                if (key == newKey)                {                    isModified = true;                }            }            //打开 App.Config            Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);            // 如果连接串已存在，首先删除它            if (isModified)            {                config.AppSettings.Settings.Remove(newKey);            }            //添加新的配置到配置文件里            config.AppSettings.Settings.Add(newKey, newValue);            //保存对配置节所做的更改            config.Save(ConfigurationSaveMode.Modified);            //强制重载配置节            ConfigurationManager.RefreshSection("appSettings");        }        /// 
        /// 对[connectionStrings]节点依据name值读取        /// 
        ///         /// 
             public static string GetConnectionString(string strName)        {            foreach (ConnectionStringSettings item in ConfigurationManager.ConnectionStrings)            {                if (item.Name == strName)                {                    return ConfigurationManager.ConnectionStrings[strName].ConnectionString;                }            }            return null;        }        /// 
        /// 更新或新增[connectionStrings]节点的子节点值        /// 
        ///         ///         public static void SetConnectionString(string newName, string newValue)        {            bool isModified = false;            // 如果要更改的Key已经存在            foreach (ConnectionStringSettings item in ConfigurationManager.ConnectionStrings)            {                if (item.Name == newName)                {                    isModified = true;                }            }            //打开 App.Config            Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);            // 如果连接串已存在，首先删除它            if (isModified)            {                config.ConnectionStrings.ConnectionStrings.Remove(newName);            }            //添加新的配置到配置文件里            ConnectionStringSettings conSetting = new ConnectionStringSettings(newName, newValue);            config.ConnectionStrings.ConnectionStrings.Add(conSetting);            //保存对配置节所做的更改            config.Save(ConfigurationSaveMode.Modified);            //强制重载配置节            ConfigurationManager.RefreshSection("connectionStrings");        }    }