XPath查询不同属性

Question

如下xml文档
<?xml version="1.0" encoding="UTF-8"?>
<root>
<tree name="top"><leafage></leafage></tree>
<tree name="middle"><leafage></leafage></tree>
<tree name="bottom"><leafage></leafage></tree>
<tree name="top"><leafage></leafage></tree>
<tree name="middle"><leafage></leafage></tree>
<tree name="bottom"><leafage></leafage></tree>
</root>
怎么用xpath查出所有的tree name
结果应为 top,middle,bottom

Answer 1

  XmlDocument xd = new XmlDocument();
            xd.Load(@"..\..\XMLFile1.xml");
            XmlNodeList node = xd.SelectNodes("root/tree");
            foreach (XmlNode cnode in node)
                Console.WriteLine(cnode.Attributes["name"].Value);

Answer 2

XPATH里怎么使用 DISTINCT ?

Answer 3

  xd.Load(@"..\..\XMLFile1.xml");
            XmlNodeList node = xd.SelectNodes("root/tree/@name");
            foreach (XmlNode cnode in node)
                Console.WriteLine(cnode.Value);这样也可以

Answer 4

//tree[not(@name=preceding-sibling::tree/@name)]/@name

Answer 5

 string str=@"<?xml version=""1.0"" encoding=""UTF-8""?> 
            <root> 
            <tree name=""top""> <leafage> </leafage> </tree> 
            <tree name=""middle""> <leafage> </leafage> </tree> 
            <tree name=""bottom""> <leafage> </leafage> </tree> 
            <tree name=""top""> <leafage> </leafage> </tree> 
            <tree name=""middle""> <leafage> </leafage> </tree> 
            <tree name=""bottom""> <leafage> </leafage> </tree> 
            </root> 
            ";
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(str);
            //*[not( name()=name(following-sibling::*) )] 
            XmlNodeList nodes = xmlDoc.SelectNodes("root/tree[not(@name=following-sibling::tree/@name)]/@name");
            foreach (XmlNode node in nodes)
            {
                Console.WriteLine(node.Value);
            }输出：top,middle,bottom

Answer 6

当然不要使用遍历啦，假如有上万的数据或更多，你要查出不同的tree name值，特别影响效率啦

Answer 7

following_sibling与preceding-sibling都可以；