遍历一个xml并输出指定节点的值

Question

我有一个类似的xml的 string，想通过遍历怎么个xml 输出我想要的element的值xml 为：<Discover xmlns="urn:schemas-microsoft-com:xml-analysis">
  <RequestType>DISCOVER_XML_METADATA</RequestType>
  <Restrictions>
    <RestrictionList>
      <ObjectExpansion>ObjectProperties</ObjectExpansion>
    </RestrictionList>
  </Restrictions>
  <Properties>
    <PropertyList>
    </PropertyList>
  </Properties>
</Discover>
我现在通过遍历，先判断是否有 ObjectExpansion 节点，如果有输出其值。请指教。

Answer 1

// XML 读取XML文件中的元素和元素属性
private static void PrintElement(XmlDocument document)
{
    XmlNodeList nodeList = document.GetElementsByTagName("*");  //获取所有的Node
    for (int i = 0; i < nodeList.Count; i++)
    {
        XmlNode node = nodeList.Item(i);
        MessageBox.Show(node.Name);                           //打印每一个node的名称
    }
}private static void PrintAttributes(XmlDocument document)
{
    XmlNodeList nodeList = document.GetElementsByTagName("*");
    XmlNamedNodeMap nameNodeMap;
    XmlElement element;
    XmlAttribute attribute;
    string attributeName;
    string attributeValue;    for (int i = 0; i < nodeList.Count; i++)
    {
        element = (XmlElement)nodeList.Item(i);
        MessageBox.Show(element.Name + ":" + element.ChildNodes[0].Value);
        nameNodeMap = element.Attributes;
        if (nameNodeMap != null)
        {
            for (int j = 0; j < nameNodeMap.Count; j++)
            {
                attribute = (XmlAttribute)nameNodeMap.Item(j);
                attributeName = attribute.Name;
                attributeValue = attribute.Value;
                MessageBox.Show("属性是：" + attributeName + "=" + attributeValue);
            }
        }
    }
}// 测试用例
private void button4_Click(object sender, EventArgs e)
{
    XmlDocument document = new XmlDocument();
    document.Load("c:\\student.xml");
    Console.WriteLine("元素是：");
    PrintElement(document);    Console.WriteLine("元素属性是：");
    PrintAttributes(document);
}

Answer 2

/// <summary>
        /// 根据节点名读出相应的节点内容
        /// </summary>
        /// <param name="parentname"></param>
        /// <param name="subname"></param>
        /// <returns></returns>
        public static string GetNode(string filepath,string parentname,string subname)
        {
            string _NodeValue=string.Empty;
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load(filepath);
            XmlNodeList nodeList = xmlDoc.SelectSingleNode("Config_Cache").ChildNodes;            
            
            foreach (XmlNode xn in nodeList)
            {                
                XmlElement xe = (XmlElement)xn;
                if (xe.GetAttribute("genre") == parentname)
                {
                    XmlNodeList nls = xe.ChildNodes;
                    foreach (XmlNode xnl in nls)
                    {
                        XmlElement xe2 = (XmlElement)xnl;
                        if (xe2.Name.ToLower() == subname.ToLower())
                        {
                            _NodeValue = xe2.InnerXml;
                            break;
                        }
                    }
                }
            }
            return _NodeValue;
        }
/// <summary>
        /// 将xml文件转换为DataSet
        /// </summary>
        /// <param name="xmlFile"></param>
        /// <returns></returns>
        public DataSet ConvertXMLFileToDataSet(string xmlFile)
        {
            StringReader stream = null;
            XmlTextReader reader = null;
            DataSet xmlDS = null;
            try
            {                lock (this)
                {
                    XmlDocument xmld = new XmlDocument();
                    xmld.Load(xmlFile);
                    stream = new StringReader(xmld.InnerXml);
                    //从stream装载到XmlTextReader
                    reader = new XmlTextReader(stream);                
                    xmlDS.ReadXml(reader);
                }
            }
            //catch (System.Exception ex)
            catch
            {
                //throw ex;
            }
            finally
            {
                if (reader != null)
                    reader.Close();
            }            return xmlDS;
        }
 /// <summary>
        /// 将DataSet转换为xml文件
        /// </summary>
        /// <param name="xmlDS"></param>
        /// <param name="xmlFile"></param>
        public static void ConvertDataSetToXMLFile(DataSet xmlDS, string xmlFile)
        {
            MemoryStream stream = null;
            XmlTextWriter writer = null;            try
            {
                stream = new MemoryStream();
                //从stream装载到XmlTextWriter
                writer = new XmlTextWriter(stream, Encoding.Unicode);                //用WriteXml方法写入文件.
                xmlDS.WriteXml(writer);
                int count = (int)stream.Length;
                byte[] arr = new byte[count];
                stream.Seek(0, SeekOrigin.Begin);
                stream.Read(arr, 0, count);                //返回Unicode编码的文本
                UnicodeEncoding utf = new UnicodeEncoding();
                StreamWriter sw = new StreamWriter(xmlFile);
                if (!System.IO.File.Exists(xmlFile))
                {
                    sw.WriteLine("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
                    sw.WriteLine(utf.GetString(arr).Trim());
                }
                sw.Close();
            }
            catch (System.Exception ex)
            {
                //throw ex;
            }
            finally
            {
                if (writer != null)
                    writer.Close();
            }
        }

Answer 3

 /// <summary>
        /// 获取节点的值
        /// </summary>
        /// <param name="xmlPath">文件路径+文件名</param>
        /// <param name="strAppKey">键名</param>
        /// <returns></returns>
        public string GetXmlNodeValue(string xmlPath, string strAppKey)
        {
            XmlNode xNode;
            string strResult = "";
            XmlDocument xDoc = new XmlDocument();
            try
            {
                xDoc.Load(xmlPath);
                if (xDoc.HasChildNodes)
                {
                    for (int i = 0; i < xDoc.ChildNodes.Count; i++)
                    {
                        xNode = xDoc.ChildNodes[i];
                        if (xNode.Name == strAppKey)
                        {
                            strResult = xNode.InnerText;
                            break;                        }
                        else
                        {
                            if (xNode.HasChildNodes)
                            {
                                strResult = GetXmlNodeValue(xNode, strAppKey);
                                if (strResult != "")
                                {
                                    break;
                                }
                            }
                        }
                    }                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            finally
            { }
            return strResult;
        }

Answer 4

使用 SelectNodes
 string _Xml = @"<Discover xmlns=""urn:schemas-microsoft-com:xml-analysis""> 
  <RequestType>DISCOVER_XML_METADATA </RequestType> 
  <Restrictions> 
    <RestrictionList> 
      <ObjectExpansion>ObjectProperties </ObjectExpansion> 
    </RestrictionList> 
  </Restrictions> 
  <Properties> 
    <PropertyList> 
    </PropertyList> 
  </Properties> 
</Discover>";            XmlDocument _Documnet = new XmlDocument();
            _Documnet.LoadXml(_Xml);            XmlNamespaceManager _Manager = new XmlNamespaceManager(_Documnet.NameTable);
            _Manager.AddNamespace("XML", "urn:schemas-microsoft-com:xml-analysis");
            XmlNodeList _List = _Documnet.SelectNodes("//XML:ObjectExpansion", _Manager);

Answer 5

使用XPath,这个用起来很方便的.