获取Xml指定节点的值

 /// <summary>  
        /// 获取指定节点的值  
        /// </summary>  
        /// <param name="strFileName">文件路径</param>  
        /// <param name="nodeName">节点名称</param>  
        /// <param name="nodeDir">指定节点所在的节点目录</param>  
        /// <returns></returns>  
        public static string GetNodeValue(string strFileName, string nodeName, string nodeDir)
        {
            string value = null;
            try
            {
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.Load(strFileName);
                XmlNode root = xmlDoc.SelectSingleNode("ufinterface");//查找<ufinterface>  
                XmlNodeList nodeList = root.SelectSingleNode(nodeDir).ChildNodes;
                foreach (XmlNode xn in nodeList)    //遍历所有子节点   
                {
                    XmlElement xe = (XmlElement)xn;  //将子节点类型转换为XmlElement类型   
                    if (xe.Name == nodeName)
                    {
                        value = xe.InnerText.Trim();
                        break;
                    }
                }
            }
            catch (Exception exp)
            {
                throw exp;
            }
            return value;
        }