.NET 基础 一步步 一幕幕[XML基础操作]

XML可扩展标记语言，标准通用标记语言的子集，是一种用于标记电子文件使其具有结构性的标记语言。

什么是XML，学他有什么用？

优点：容易读懂，格式标准任何语言都内置了XML分析引擎，不用单独进行文件分析引擎得编写。

XML语法规范：标签（Tag）、嵌套（Nest）、属性。标签要闭合，属性值要用””包围，标签可以相互嵌套。

大小写敏感。

XML树，父节点、子节点、兄弟节点。

写入一个XML文件

//1、创建一个XML文档对象

            XmlDocument doc = new XmlDocument();

            //2、创建第一行描述信息

            XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);

            //3、将创建的第一行数据添加到文档中

            doc.AppendChild(dec);

            //4、给文档添加根节点

            XmlElement books = doc.CreateElement("Books");

            //5、将根节点添加给文档对象

            doc.AppendChild(books);

 

            //6、给根节点添加子节点

            XmlElement book1 = doc.CreateElement("Book");

            //将子节点book1添加到根节点下

            books.AppendChild(book1);

 

            //7、给book1添加子节点

            XmlElement bookName1 = doc.CreateElement("BookName");

            //8、设置标签中显示的文本

            bookName1.InnerText = "水浒传";

            book1.AppendChild(bookName1);

 

            XmlElement author1 = doc.CreateElement("Author");

            author1.InnerText = "<authorName>匿名</authorName>";

            book1.AppendChild(author1);

 

            XmlElement price1 = doc.CreateElement("Price");

            price1.InnerXml = "<authorName>匿名</authorName>";

            book1.AppendChild(price1);

 

            XmlElement des1 = doc.CreateElement("Des");

            des1.InnerXml = "好看，顶！~！！！！";

            book1.AppendChild(des1);

 

            Console.WriteLine("保存成功");

            doc.Save("Book.xml");

演示结果：

<?xml version="1.0" encoding="utf-8" ?>

<Books>

  <Book>

    <BookName>水浒传</BookName>

    <Author>XXX</Author>

    <Price>100RMB</Price>

    <Des>好看！！经典！！！！顶！！！！</Des>

  </Book>

  <Book>

    <BookName>三国演义</BookName>

    <Author>XXX</Author>

    <Price>200RMB</Price>

    <Des>好看，顶！！！！</Des>

  </Book>

</Books>

 

添加带属性的XML文档

XmlDocument doc = new XmlDocument();

            XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);

            doc.AppendChild(dec);

 

            XmlElement order = doc.CreateElement("Order");

            doc.AppendChild(order);

 

            XmlElement customerName = doc.CreateElement("CustomerName");

            customerName.InnerXml = "刘洋";

            order.AppendChild(customerName);

 

            XmlElement orderNumber = doc.CreateElement("OrderNumber");

            orderNumber.InnerXml = "10000";

            order.AppendChild(orderNumber);

 

            XmlElement items = doc.CreateElement("Items");

            order.AppendChild(items);

 

            XmlElement orderItem1 = doc.CreateElement("OrderItem");

            orderItem1.SetAttribute("Name", "码表");

            orderItem1.SetAttribute("Count", "100001");

            items.AppendChild(orderItem1);

 

            XmlElement orderItem2 = doc.CreateElement("OrderItem");

            orderItem2.SetAttribute("Name", "雨衣");

            orderItem2.SetAttribute("Count", "1");

            items.AppendChild(orderItem2);

            doc.Save("Order.xml");

 

文档对象模型

对象实体：

Public class Student

    {

        public int Age { get; set; }

        public string Name { get; set; }

        public int ID { get; set; }

        public char Gender { get; set; }

    }

 

List<Student> list = new List<Student>();

            list.Add(new Student() { ID = 1, Name = "yhb", Gender = '男', Age = 30 });

            list.Add(new Student() { ID = 2, Name = "wl", Gender = '女', Age = 20 });

            list.Add(new Student() { ID = 3, Name = "刘德华", Gender = '男', Age = 50 });

            list.Add(new Student() { ID = 4, Name = "张学友", Gender = '男', Age = 60 });

            list.Add(new Student() { ID = 5, Name = "哥哥", Gender = '男', Age = -10 });

 

            XmlDocument doc = new XmlDocument();

            XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);

 

            doc.AppendChild(dec);

 

            XmlElement person = doc.CreateElement("Person");

            doc.AppendChild(person);

 

            //通过循环List集合，获得所有对象 以节点的形式添加到XML文档中

            for (int i = 0; i < list.Count; i++)

            {

                XmlElement student = doc.CreateElement("Student");

                student.SetAttribute("studentID", list[i].ID.ToString());

                XmlElement name = doc.CreateElement("Name");

                name.InnerXml = list[i].Name;

                XmlElement age = doc.CreateElement("Age");

                age.InnerXml = list[i].Age.ToString();

                XmlElement gender = doc.CreateElement("Gender");

                gender.InnerXml = list[i].Gender.ToString();

                //添加

                person.AppendChild(student);

                student.AppendChild(name);

                student.AppendChild(age);

                student.AppendChild(gender);

            }

            doc.Save("Student.xml");

  对xml文档实现增删改查

         //XMLDocument

           #region 对xml文档实现追加的需求

           XmlDocument doc = new XmlDocument();

           //首先判断xml文档是否存在 如果存在 则追加  否则创建一个

           if (File.Exists("Student.xml"))

           {

               //加载进来

               doc.Load("Student.xml");

               //追加

               //获得根节点 给根节点添加子节点

               XmlElement person = doc.DocumentElement;

 

               XmlElement student = doc.CreateElement("Student");

               student.SetAttribute("studentID", "10");

               person.AppendChild(student);

 

               XmlElement name = doc.CreateElement("Name");

               name.InnerXml = "我是新来哒";

               student.AppendChild(name);

 

               XmlElement age = doc.CreateElement("Age");

               age.InnerXml = "18";

               student.AppendChild(age);

 

               XmlElement gender = doc.CreateElement("Gender");

               gender.InnerXml = "女";

               student.AppendChild(gender);

 

           }

           else

           {

               //不存在

               XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);

               doc.AppendChild(dec);

               XmlElement person = doc.CreateElement("Person");

               doc.AppendChild(person);

               XmlElement student = doc.CreateElement("Student");

               student.SetAttribute("studentID", "110");

               person.AppendChild(student);

               XmlElement name = doc.CreateElement("Name");

               name.InnerXml = "张三三李思思";

               student.AppendChild(name);

               XmlElement age = doc.CreateElement("Age");

               age.InnerXml = "28";

               student.AppendChild(age);

 

               XmlElement gender = doc.CreateElement("Gender");

               gender.InnerXml = "男";

               student.AppendChild(gender);

           }

           doc.Save("Student.xml");

           Console.WriteLine("保存成功");

           #endregion

           #region 读取XML文档

           XmlDocument doc = new XmlDocument();

           doc.Load("OrDER.xml");

           还是 先获得根节点

           XmlElement order = doc.DocumentElement;

           获得根节点下面的所有子节点

           XmlNodeList xnl = order.ChildNodes;

           foreach (XmlNode item in xnl)

           {

               Console.WriteLine(item.InnerText);

           }

           XmlElement items = order["Items"];

           XmlNodeList xnl2 = items.ChildNodes;

           foreach (XmlNode item in xnl2)

           {

               Console.WriteLine(item.Attributes["Name"].Value);

               Console.WriteLine(item.Attributes["Count"].Value);

               if (item.Attributes["Name"].Value == "手套")

               {

                   item.Attributes["Count"].Value = "新来哒";

               }

           }

           doc.Save("OrDER.xml");

           #endregion

           #region 使用XPath的方式来读取XML文件

           XmlDocument doc = new XmlDocument();

           doc.Load("order.xml");

           //获得根节点

           XmlElement order = doc.DocumentElement;

           XmlNode xn = order.SelectSingleNode("/Order/Items/OrderItem[@Name='雨衣']");

           Console.WriteLine(xn.Attributes["Name"].Value);

           xn.Attributes["Count"].Value = "woshi new";

           doc.Save("order.xml");

           Console.WriteLine("保存成功");

           #endregion

           XmlDocument doc = new XmlDocument();

           doc.Load("order.xml");

           //doc.RemoveAll();不行 根节点不允许删除

           XmlElement order = doc.DocumentElement;

           order.RemoveAll(); 移除根节点下的所有子节点

           XmlNode xn = order.SelectSingleNode("/Order/Items/OrderItem[@Name='雨衣']");

           //让orderItem去删除属性

           XmlNode orderItem = order.SelectSingleNode("/Order/Items/OrderItem");

           //获得Items节点

           XmlNode items = order["Items"];//order.SelectSingleNode("/Order/Items");

           items.RemoveChild(xn); //移除当前节点

            //orderItem.RemoveAttributeNode(xn.Attributes["Count"]);

           xn.Attributes.RemoveNamedItem("Count");

           doc.Save("order.xml");

           Console.WriteLine("删除成功");

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