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();

    }

}