C#读写config配置文件的方法

<?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;
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;
    }
  }
}

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);
      }
    }
  }