利用XmlDocument操作XML文件

利用XmlDocument可以方便的操作XML文件。

1.操作XML文件基本方法

（1）添加对System.Xml的引用，并使用using语句添加引用；

（2）假设要读取的XML文件如下：

<?xml version="1.0" encoding="utf-8"?>
<Students>
  <Student>
    <Name>张靓靓</Name>
    <Age>20</Age>
    <Hobby>唱歌歌</Hobby>
  </Student>
  <Student>
    <Name>周杰杰</Name>
    <Age>22</Age>
    <Hobby>耍双节棍棍</Hobby>
  </Student>
</Students>

（3）编写程序，增加节点：

        private static void AddNode()
        {
            XmlDocument myXml = new XmlDocument();
            myXml.Load("Student.xml"); //读取指定的XML文档
            XmlNode students = myXml.SelectSingleNode("Students");//读取Students节点
            XmlElement newStudent = myXml.CreateElement("Student");

            newStudent.SetAttribute("班级", "10软件");
            XmlElement name = myXml.CreateElement("Name");
            name.InnerText = "张三";
            XmlElement age = myXml.CreateElement("Age");
            age.InnerText = "20";
            XmlElement hobby = myXml.CreateElement("Hobby");
            hobby.InnerText = "看书";
            newStudent.AppendChild(name);
            newStudent.AppendChild(age);
            newStudent.AppendChild(hobby);
            students.AppendChild(newStudent);
            myXml.Save("Student.xml");
        }

（4）删除节点：

        private static void DelNode()
        {
            XmlDocument myXml = new XmlDocument();
            myXml.Load("Student.xml"); //读取指定的XML文档
            XmlNode student= myXml.SelectSingleNode("//Student[Name='张德友']");//读取节点
            if(student!=null)
                student.ParentNode.RemoveChild(student);
            myXml.Save("Student.xml");
        }

（5）修改节点的值：

        private static void ChangeNode()
        {
            XmlDocument myXml = new XmlDocument();
            myXml.Load("Student.xml"); //读取指定的XML文档
            XmlNodeList students = myXml.DocumentElement.ChildNodes;
            foreach (XmlNode student in students)
            {
                XmlElement name=student.SelectSingleNode("Name") as XmlElement;//读取节点
                if (name.InnerText.Equals("张三"))
                    name.InnerText = "李四";
            }
            myXml.Save("Student.xml");
        }

（6）读取XML文件：

        private static void ReadNode()
        {
            XmlDocument myXml = new XmlDocument();
            myXml.Load("Student.xml"); //读取指定的XML文档
            XmlNodeList students = myXml.DocumentElement.ChildNodes;//读取所有Student节点
            foreach (XmlNode student in students)// 对子节点进行循环
            {
                foreach (XmlNode node in student.ChildNodes)
                {
                    //将每个节点的内容显示出来
                    switch (node.Name)
                    {
                        case "Name":
                            Console.WriteLine("姓名:{0}", node.InnerText);
                            break;
                        case "Age":
                            Console.WriteLine("年龄:{0}", node.InnerText);
                            break;
                        case "Hobby":
                            Console.WriteLine("爱好:{0}", node.InnerText);
                            break;
                    }
                }
            }
        }

2  操作ASP.NET网站站点地图文件：

站点地图文件Web.sitemap的格式如下：

<?xml version="1.0" encoding="utf-8"?>
<siteMapNode url="default.aspx" title="新书推荐" description="">
  <siteMapNode title=" C#" url="BookList.aspx?typeid=1" description="" />
  <siteMapNode title=".NET" url="BookList.aspx?typeid=25" description="" />
</siteMapNode>

    /// <summary>
    /// 更新全部XML
    /// </summary>
    private void ModifyXml()
    {       
        xmldocTree.Load(Server.MapPath(CATAGORYXML));
        xmldocTree.SelectSingleNode("siteMapNode").InnerText="";
        foreach (Category catagory in CategoryManager.GetAllCategories())
        {
            MakeChild(catagory);
        }
        xmldocTree.Save(Server.MapPath(CATAGORYXML));
    }
    /// <summary>
    /// 设置子节点
    /// </summary>
    /// <param name="catagory"></param>
    private void MakeChild(Category catagory)
    {
        XmlElement xmlelNode = xmldocTree.CreateElement("siteMapNode");
        xmlelNode.SetAttribute("title", catagory.Name);
        xmlelNode.SetAttribute("url", BOOKLISTURL + catagory.Id.ToString());
        xmlelNode.SetAttribute("description", "");
        xmldocTree.SelectSingleNode("siteMapNode").AppendChild(xmlelNode);
    }