C# Winform 修改app.config文件

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <connectionStrings></connectionStrings>
    <appSettings>
        <addkey="Server" value=" "/>
        <addkey="initial catalog" value=" "></add>
        <addkey="uid" value=" "></add>
        <addkey="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>
        privatevoid 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");
        }