C#读写config配置文件

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="ServerIP" value="127.0.0.1"></add>
    <add key="DataBase" value="WarehouseDB"></add>
    <add key="user" value="sa"></add>
    <add key="password" value="sa"></add>
  </appSettings>
</configuration>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Configuration;
using System.ServiceModel.Configuration;

namespace ConfigTest
{
    public static class ConfigHelper
    {
        ///<summary> 
        ///依据连接串名字connectionName返回数据连接字符串  
        ///</summary> 
        ///<param name="connectionName"></param> 
        ///<returns></returns> 
        public static string GetConnectionStringsConfig(string connectionName)
        {
            //默认config读取
            //string connectionString =
            //        ConfigurationManager.ConnectionStrings[connectionName].ConnectionString.ToString();

            //指定config文件读取
            string file = System.Windows.Forms.Application.ExecutablePath;
            Configuration config = ConfigurationManager.OpenExeConfiguration(file);
            string connectionString = config.ConnectionStrings.ConnectionStrings[connectionName].ConnectionString.ToString();
            //Console.WriteLine(connectionString);
            return connectionString;
        }

        ///<summary> 
        ///更新连接字符串  
        ///</summary> 
        ///<param name="newName">连接字符串名称</param> 
        ///<param name="newConString">连接字符串内容</param> 
        ///<param name="newProviderName">数据提供程序名称</param> 
        public static void UpdateConnectionStringsConfig(string newName, string newConString, string newProviderName)
        {
            // 打开可执行的配置文件*.exe.config  
            //Configuration config =
            //    ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

            //指定config文件读取
            string file = System.Windows.Forms.Application.ExecutablePath;
            Configuration config = ConfigurationManager.OpenExeConfiguration(file);

            bool exist = false;    //记录该连接串是否已经存在  
            //如果要更改的连接串已经存在  
            //if (ConfigurationManager.ConnectionStrings[newName] != null) //默认config
            //{
            //    exist = true;
            //}
            if (config.ConnectionStrings.ConnectionStrings[newName] != null)
            {
                exist = true;
            }
            //新建一个连接字符串实例  
            ConnectionStringSettings mySettings =
                new ConnectionStringSettings(newName, newConString, newProviderName);
            
            // 如果连接串已存在，首先删除它  
            if (exist)
            {
                config.ConnectionStrings.ConnectionStrings.Remove(newName);
            }
            // 将新的连接串添加到配置文件中.  
            config.ConnectionStrings.ConnectionStrings.Add(mySettings);
            // 保存对配置文件所作的更改  
            config.Save(ConfigurationSaveMode.Modified);
            // 强制重新载入配置文件的ConnectionStrings配置节  
            ConfigurationManager.RefreshSection("ConnectionStrings");
        }

        ///<summary> 
        ///返回*.exe.config文件中appSettings配置节的value项  
        ///</summary> 
        ///<param name="strKey"></param> 
        ///<returns></returns> 
        public static string GetAppConfig(string strKey)
        {
            //foreach (string key in ConfigurationManager.AppSettings)
            //{
            //    if (key == strKey)
            //    {
            //        return ConfigurationManager.AppSettings[strKey];
            //    }
            //}
            string file = System.Windows.Forms.Application.ExecutablePath;
            Configuration config = ConfigurationManager.OpenExeConfiguration(file);
            foreach (string key in config.AppSettings.Settings.AllKeys)
            {
                if (key == strKey)
                {
                    return config.AppSettings.Settings[strKey].Value.ToString();
                }
            }
            return null;
        }

        ///<summary>  
        ///在*.exe.config文件中appSettings配置节增加一对键值对  
        ///</summary>  
        ///<param name="newKey"></param>  
        ///<param name="newValue"></param>  
        public static void UpdateAppConfig(string newKey, string newValue)
        {
            // Open App.Config of executable  
            //Configuration config =
            //    ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            string file = System.Windows.Forms.Application.ExecutablePath;
            Configuration config = ConfigurationManager.OpenExeConfiguration(file);
            bool exist = false;
            foreach (string key in config.AppSettings.Settings.AllKeys)
            {
                if (key == newKey)
                {
                    exist = true;
                }
            }

            // You need to remove the old settings object before you can replace it  
            if (exist)
            {
                config.AppSettings.Settings.Remove(newKey);
            }
            // Add an Application Setting.  
            config.AppSettings.Settings.Add(newKey, newValue);
            // Save the changes in App.config file.  
            config.Save(ConfigurationSaveMode.Modified);
            // Force a reload of a changed section.  
            ConfigurationManager.RefreshSection("appSettings");
        }

        /// <summary>
        /// 修改system.serviceModel下所有服务终结点的IP地址和端口号
        /// </summary>
        /// <param name="serverIPAddress"></param>
        /// <param name="serverPort"></param>
        public static void UpdateConfig(string serverIPAddress, string serverPort)
        {
            //Configuration config = ConfigurationManager.OpenExeConfiguration(Assembly.GetEntryAssembly().Location);  
            //Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            string file = System.Windows.Forms.Application.ExecutablePath + ".config";
            Configuration config = ConfigurationManager.OpenExeConfiguration(file);
            ConfigurationSectionGroup sct = config.SectionGroups["system.serviceModel"];
            ServiceModelSectionGroup serviceModelSectionGroup = sct as ServiceModelSectionGroup;
            ClientSection clientSection = serviceModelSectionGroup.Client;

            foreach (ChannelEndpointElement item in clientSection.Endpoints)
            {
                string pattern = "://.*/";
                string address = item.Address.ToString();
                string replacement = string.Format("://{0}:{1}/", serverIPAddress, serverPort);
                address = Regex.Replace(address, pattern, replacement);
                item.Address = new Uri(address);
            }
            config.Save(ConfigurationSaveMode.Modified);
            ConfigurationManager.RefreshSection("system.serviceModel");
        }

        /// <summary>
        /// 修改system.serviceModel下所有服务终结点的IP地址
        /// </summary>
        /// <param name="serverIPAddress"></param>
        public static void UpdateConfig(string serverIPAddress)
        {
            //Configuration config = ConfigurationManager.OpenExeConfiguration(Assembly.GetEntryAssembly().Location);  
            //Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            string file = System.Windows.Forms.Application.ExecutablePath + ".config";
            Configuration config = ConfigurationManager.OpenExeConfiguration(file);
            ConfigurationSectionGroup sct = config.SectionGroups["system.serviceModel"];
            ServiceModelSectionGroup serviceModelSectionGroup = sct as ServiceModelSectionGroup;
            ClientSection clientSection = serviceModelSectionGroup.Client;

            foreach (ChannelEndpointElement item in clientSection.Endpoints)
            {
                string pattern = "://.*:";
                string address = item.Address.ToString();
                string replacement = string.Format("://{0}:", serverIPAddress);
                address = Regex.Replace(address, pattern, replacement);
                item.Address = new Uri(address);
            }
            config.Save(ConfigurationSaveMode.Modified);
            ConfigurationManager.RefreshSection("system.serviceModel");
        }
    }
}

    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                //string file = System.Windows.Forms.Application.ExecutablePath + ".config";
                //string file1 = AppDomain.CurrentDomain.SetupInformation.ConfigurationFile;
                string serverIP = ConfigHelper.GetAppConfig("ServerIP");
                string db = ConfigHelper.GetAppConfig("DataBase");
                string user = ConfigHelper.GetAppConfig("user");
                string password = ConfigHelper.GetAppConfig("password");

                Console.WriteLine(serverIP);
                Console.WriteLine(db);
                Console.WriteLine(user);
                Console.WriteLine(password);

                ConfigHelper.UpdateAppConfig("ServerIP", "192.168.1.11");
                string newIP = ConfigHelper.GetAppConfig("ServerIP");
                Console.WriteLine(newIP);

                Console.ReadKey();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }
    }