在web应用程序中在网页中对Web.config文件进行数据连接配置

 using System;
 using System.Collections.Generic;
 using System.Configuration;
 using System.Web.Configuration;
 using System.Text;
 using System.IO;

     /// <summary>
 /// SystemConfig 的摘要说明
 /// </summary>
 public static class SystemConfig
 {
     private static Configuration ConfigFile;
     private static KeyValueConfigurationCollection SysConfig;

     static SystemConfig()
     {
         ConfigFile = WebConfigurationManager.OpenWebConfiguration("/");
         SysConfig = ConfigFile.AppSettings.Settings;
     }

     public static void setValue(string configfilepath, string key, string value)
     {
         ExeConfigurationFileMap map = new ExeConfigurationFileMap();
         map.ExeConfigFilename = configfilepath;
         ConfigFile = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None);
         SysConfig = ConfigFile.AppSettings.Settings;

         KeyValueConfigurationElement el = SysConfig[key];
         if (el == null)
         {
             SysConfig.Add(key, value);
         }
         else
         {
             el.Value = value;
         }

         //同步更新
         ConfigFile.Save();

     }

 }