C# Winform 修改app.config文件

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <connectionStrings></connectionStrings>
    <appSettings>
        <add key="Server" value=" "/>
        <add key="initial catalog" value=" "></add>
        <add key="uid" value=" "></add>
        <add key="pwd" value=" "></add>
    </appSettings>
</configuration>



#region  方法保存修改的设置
        /// <summary>
        /// 方法保存修改的设置
        /// </summary>
        /// <param name="ConnenctionString"></param>
        /// <param name="strKey"></param>
        private void SaveConfig(string ConnenctionString, string strKey)
        {
            XmlDocument doc = new XmlDocument();
            //获得配置文件的全路径
            string strFileName = AppDomain.CurrentDomain.SetupInformation.ConfigurationFile;
            doc.Load(strFileName);
            //找出名称为“add”的所有元素
            XmlNodeList nodes = doc.GetElementsByTagName("add");
            for (int i = 0; i < nodes.Count; i++)
            {
                //获得将当前元素的key属性
                XmlAttribute att = nodes[i].Attributes["key"];
                //根据元素的第一个属性来判断当前的元素是不是目标元素
                if (att.Value == strKey)
                {
                    //对目标元素中的第二个属性赋值
                    att = nodes[i].Attributes["value"];
                    att.Value = ConnenctionString;
                    break;
                }
            }
            //保存上面的修改
            doc.Save(strFileName);
        }
        #endregion

//调用方法修改app.config文件
private void btnOK_Click_1(object sender, EventArgs e)
        {
                SaveConfig("WWW-8CB7FB23DD4","Server");
                SaveConfig("myehrce","initial catalog");
                SaveConfig("sa", "uid");
                SaveConfig("123","pwd");
        }