winform中app.config的动态读写操作

在winform中使用程序动态读取和修改App.config里面的appSettings当中的Value值，解决winform中没有的修改和修改后不能及时取得其值的问题：
        //写操作
        public static void SetValue(string AppKey, string AppValue)
        {
            XmlDocument xDoc = new XmlDocument();
            //获取可执行文件的路径和名称
            xDoc.Load(System.Windows.Forms.Application.ExecutablePath + ".config");
            XmlNode xNode;
            XmlElement xElem1;
            XmlElement xElem2;
            xNode = xDoc.SelectSingleNode("//appSettings");
            xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@key='" + AppKey + "']");
            if (xElem1 != null) xElem1.SetAttribute("value", AppValue);
            else
            {
                xElem2 = xDoc.CreateElement("add");
                xElem2.SetAttribute("key", AppKey);
                xElem2.SetAttribute("value", AppValue);
                xNode.AppendChild(xElem2);
            }
            xDoc.Save(System.Windows.Forms.Application.ExecutablePath + ".config");
        }
        //读操作
        public string GetConfigValue(string appKey)
        {
            XmlDocument xDoc = new XmlDocument();
            try
            {
                xDoc.Load(System.Windows.Forms.Application.ExecutablePath + ".config");
                XmlNode xNode;
                XmlElement xElem;
                xNode = xDoc.SelectSingleNode("//appSettings");
                xElem = (XmlElement)xNode.SelectSingleNode("//add[@key='" + appKey + "']");
                if (xElem != null)
                    return xElem.GetAttribute("value");
                else
                    return "";
            }
            catch (Exception)
            {
                return "";
            }
        }