C#读写config配置文件应用程序配置文件（App.config）是标准的XML 文件，XML 标记和属性是区分大小写的。

它是可以按需要更改的，开发人员可以使用配置文件来更改设置，而不必重编译应用程序。

对于一个config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>对config配置文件的读写类：using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Text.RegularExpressions;using System.Configuration;using System.ServiceModel;using System.ServiceModel.Configuration;namespace NetUtilityLib{public static class ConfigHelper{//依据连接串名字connectionName返回数据连接字符串public static string GetConnectionStringsConfig(string connectionName){//指定config文件读取string file = System.Windows.Forms.Application.ExecutablePath;System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(file);string connectionString =config.ConnectionStrings.ConnectionStrings[connectionName].ConnectionString.ToString();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) {//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 (config.ConnectionStrings.ConnectionStrings[newName] != null){exist = true;}// 如果连接串已存在，首先删除它if (exist){config.ConnectionStrings.ConnectionStrings.Remove(newName);}//新建一个连接字符串实例ConnectionStringSettings mySettings =new ConnectionStringSettings(newName, newConString, newProviderName);// 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){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){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;}}if (exist){config.AppSettings.Settings.Remove(newKey);}config.AppSettings.Settings.Add(newKey, newValue);config.Save(ConfigurationSaveMode.Modified);ConfigurationManager.RefreshSection("appSettings");}// 修改system.serviceModel下所有服务终结点的IP地址public static void UpdateServiceModelConfig(string configPath, string serverIP){Configuration config = ConfigurationManager.OpenExeConfiguration(configPath);ConfigurationSectionGroup sec = config.SectionGroups["system.serviceModel"];ServiceModelSectionGroup serviceModelSectionGroup = sec as ServiceModelSectionGroup;ClientSection clientSection = serviceModelSectionGroup.Client;foreach (ChannelEndpointElement item in clientSection.Endpoints){string pattern = @"\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b";string address = item.Address.ToString();string replacement = string.Format("{0}", serverIP);address = Regex.Replace(address, pattern, replacement);item.Address = new Uri(address);}config.Save(ConfigurationSaveMode.Modified);ConfigurationManager.RefreshSection("system.serviceModel");}// 修改applicationSettings中App.Properties.Settings中服务的IP地址public static void UpdateConfig(string configPath, string serverIP){Configuration config = ConfigurationManager.OpenExeConfiguration(configPath);ConfigurationSectionGroup sec = config.SectionGroups["applicationSettings"];ConfigurationSection configSection = sec.Sections["DataService.Properties.Settings"];ClientSettingsSection clientSettingsSection = configSection as ClientSettingsSection;if (clientSettingsSection != null){SettingElement element1 =clientSettingsSection.Settings.Get("DataService_SystemManagerWS_SystemManagerWS");if (element1 != null){clientSettingsSection.Settings.Remove(element1);string oldValue = element1.Value.ValueXml.InnerXml;element1.Value.ValueXml.InnerXml = GetNewIP(oldValue, serverIP);clientSettingsSection.Settings.Add(element1);}SettingElement element2 =clientSettingsSection.Settings.Get("DataService_EquipManagerWS_EquipManagerWS");if (element2 != null){clientSettingsSection.Settings.Remove(element2);string oldValue = element2.Value.ValueXml.InnerXml;element2.Value.ValueXml.InnerXml = GetNewIP(oldValue, serverIP);clientSettingsSection.Settings.Add(element2);}}config.Save(ConfigurationSaveMode.Modified);ConfigurationManager.RefreshSection("applicationSettings");}private static string GetNewIP(string oldValue, string serverIP){string pattern = @"\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b";string replacement = string.Format("{0}", serverIP);string newvalue = Regex.Replace(oldValue, pattern, replacement);return newvalue;}}}测试代码如下：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);}}}。