<?xml version="1.0" encoding="utf-8" ?><configuration> <appSettings> <add key="testkey" value="0"></add> </appSettings></configuration>

using System.Configuration;namespace pcauto{ public static class ConfigHelper {   ///<summary>    ///返回*.exe.config文件中appSettings配置節的value項    ///</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配置節增加一對鍵值對    ///</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");  }   }}

ConfigHelper.GetAppConfig("testkey")

ConfigHelper.UpdateAppConfig("testkey", "abc");