/// <summary>
        /// 根据给定的配置文件中key获取其对应的value
        /// </summary>
        /// <param name="key">需要查找的key</param>
        /// <returns>可以对应的value</returns>
        public string GetAppSettingValue(string key)
        {
            //创建XML读取对象
            XmlDocument doc = new XmlDocument();
            //获取XML文件的路径创建文件流读取器
            StreamReader _read = new StreamReader(GlobalCache.Instance.ConfigFile);
            //加载XML文件
            doc.Load(_read);
            //释放文件流读取器资源
            _read.Close();
            //遍历XML文件查找所需节点的Value值
            foreach (XmlNode node in doc.DocumentElement["appSettings"])
            {
                //查找节点,排除注释
                if (node.Attributes != null && string.Compare(key, node.Attributes["key"].Value) == 0)
                {//返回key对应的value
                    return node.Attributes["value"].Value;
                }
            }
            return "";
        }
 

文件路径的获取： 代码
FileAccess fileAccess = new FileAccess();
                //获取应用程序路径
                GlobalCache.Instance.AppPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().GetName().CodeBase)
                    + @"\";
                //获取配置文件路径
                GlobalCache.Instance.ConfigFile = GlobalCache.Instance.AppPath + @"Config\Appconfig.xml";