/// <param name="path">.exe.config檔案的路徑</param> 
        /// <param name="appKey">"key"的值</param> 
        /// <returns>返回"value"的值</returns> 
        internal static string GetConfigValue(string path, string appKey)
        {
            XmlDocument xDoc = new XmlDocument();
            XmlNode xNode;
            XmlElement xElem = null;
            try
            {
                xDoc.Load(path);
                xNode = xDoc.SelectSingleNode("//appSettings");
                xElem = (XmlElement)xNode.SelectSingleNode("//add[@key=\"" + appKey + "\"]");
            }
            catch (XmlException ex)
            {
            }
            if (xElem != null)
                return xElem.GetAttribute("value");
            else
                return "";
        }
 

 /// <param name="path">.exe.config檔案的路徑</param> 
        /// <param name="appKey">"key"的值</param> 
        /// <param name="appValue">"value"的值</param> 
        internal static void SetConfigValue(string path, string appKey, string appValue)
        {
            XmlDocument xDoc = new XmlDocument();
            try
            {
                xDoc.Load(path);

                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(applicationPath + "\\" + path);
            }
            catch (XmlException ex)
            {
            }
        }