LINQ之路二：TO XML(2)

参考文档：http://www.cnblogs.com/lifepoem/archive/2011/12/06/2277554.html
一：X-DOM介绍

二：XElement包含了管理属性的方法，以及Name和Value成员。

using System.Xml.Linq; 
XElement lastName = new XElement("lastname", "Bloggs");
//他会创建这样的节点 <lastname>Bloggs</lastname>

XElement StuClass = new XElement("Class");
XElement Student = new XElement("Student", "小明");
StuClass.Add(Student);
Console.WriteLine(StuClass.ToString());
//<Class>
//  <Student>小明</Student>
//</Class>

//增加属性
//< Body >
//  < Student Age = "15" Sex = "男" Name = "小明" />
//</ Body >
XElement StuClass = new XElement("Body");
XElement Student = new XElement("Student");
XAttribute[] parm = new XAttribute[] 
            {
                new XAttribute("Age", 15),
                new XAttribute("Sex", "男"),
                new XAttribute("Name", "小明")
            };
Student.Add(parm);
StuClass.Add(Student);
Console.WriteLine(StuClass.ToString());

三：XDocumentXelement和XDocument都提供了静态的Load和Parse方法，他们用来创建X-DOM tree。Load用来从file、URI、Stream、TextReader或XmlReader创建X-DOM
Parse用来从string创建X-DOM

XDocument doc = XDocument.Load(string url);
  XElement config = XElement.Parse(
                @"<configuration>
                    <client enabled='true'>
                        <timeout>30</timeout>
                    </client>
                </configuration>");

四：简单例子

  IEnumerable<XElement> ChildElements= XElement.Elements();//XElement下的子元素

XDocument xd = new XDocument(
              new XElement("MyElement",
               new XElement("first",
               new XAttribute("color","red"),
               new XAttribute("size", "small")
               ),
               new XElement("second",
               new XAttribute("color", "red"),
               new XAttribute("size", "medim")
               ),
               new XElement("third",
               new XAttribute("color", "blue"),
               new XAttribute("size", "large")
               )
              )  
             );
            XElement root = xd.Element("MyElement");
            var query = from e in root.Elements()
                        where e.Name.ToString().Length == 5
                        select e;
            foreach(XElement q in query)
            {
                Console.WriteLine("Name:{0},color:{1},size:{2}",
                    q.Name,
                    q.Attribute("color").Value,
                    q.Attribute("size").Value
                    );
            }

例子2

using System.Xml.Linq;
private void LoadXmlByLinq()
        {
            XDocument xml = XDocument.Load(@"d:\test.xml");
            XElement root = xml.Element("Students");//获取第一个子节点
            var node = from e in root.Elements()//遍历根节点下的节点
                       where Convert.ToInt32(e.Attribute("age").Value)>21
                       select e;
            string s = "";
            foreach (XElement xnode in node)
            {
                s += xnode.Attribute("age").Value;
                s += xnode.Attribute("name").Value;
            }
            MessageBox.Show(s);//22魅族
        }