------------LINQ操作XML--------------

        /// <summary>

        /// 1、创建BookStore.xml的XML文件，由函数CreateXmlFile()完成

        /// </summary>

        /// <param name="xmlpath">XML文件的路径</param>

        private static void CreateXmlFile(string xmlpath)

        {

            XDocument doc = new XDocument(              ///创建XDocument类的实例

                new XDeclaration("1.0", "utf-8", "yes"),///XML的声明，包括版本，编码，xml文件是否独立

                new XElement("Books",                   ///添加根节点

                    new XElement("Book",                ///添加一个节点

                        new XAttribute("BookID", "001"),///添加属性BookID

                        new XElement("BookNo", "0001"), ///添加元素BookNo

                        new XElement("BookName", "Book 0001"),///添加元素BookName

                        new XElement("BookPrice", "40"),///添加元素BookPrice

                        new XElement("BookRemark", "This is a book 0001")///添加元素BookRemark

                                 )

                             )

                );

            ///保存XML文件到指定地址

            doc.Save(xmlpath);

            Console.WriteLine(doc);

        }

      //调用函数CreateXmlFile(string xmlpath)

      static void Main(string[] args)

        {

            ///创建一个名为BookStore.xml的xml文件

            Program.CreateXmlFile(@"C:\BookStore.xml");

         }

        /// <summary>

        /// 2、添加元素

        /// </summary>

        /// <param name="xmlpath">XML文件的路径</param>

        private static void AddXmlElement(string xmlpath)

        {

            ///导入XML文件

            XElement xe = XElement.Load(xmlpath);

            ///创建一个新节点

            XElement book1 = new XElement("Book",

                               new XAttribute("BookID", "002"),

                               new XElement("BookNo", "0002"),

                               new XElement("BookName", "Book 0002"),

                               new XElement("BookPrice", "50"),

                               new XElement("BookRemark", "This is a book 0002")

                );

            ///添加节点到XML文件中，并保存

            xe.Add(book1);

            ///创建一个新节点

            XElement book2 = new XElement("Book",

                               new XAttribute("BookID", "003"),

                               new XElement("BookNo", "0003"),

                               new XElement("BookName", "Book 0003"),

                               new XElement("BookPrice", "30"),

                               new XElement("BookRemark", "This is a book 0003")

                );

            ///添加节点到XML文件中，并保存

            xe.Add(book2);

            ///创建一个新节点

            XElement book3 = new XElement("Book",

                               new XAttribute("BookID", "004"),

                               new XElement("BookNo", "0004"),

                               new XElement("BookName", "Book 0004"),

                               new XElement("BookPrice", "60"),

                               new XElement("BookRemark", "This is a book 0004")

                );

            ///添加节点到XML文件中

            xe.Add(book3);

            ///保存到XML文件中

            xe.Save(xmlpath);



            Console.WriteLine(xe);

        }

            //调用函数AddXmlElement(string xmlpath)

            ///添加XML元素

            Program.AddXmlElement(@"C:\BookStore.xml");

        /// <summary>

        ///  3、修改XML文件的元素

        /// </summary>

        /// <param name="xmlpath">XML文件的路径</param>

        /// <param name="strElement">指定的修改元素</param>

        private static void ModifyXmlElement(string xmlpath, string strElement)

        {

            XElement xe = XElement.Load(xmlpath);

            ///查询修改的元素

            IEnumerable<XElement> element = from e in xe.Elements("Book")

                                            where e.Attribute("BookID").Value == strElement

                                            select e;

            ///修改元素

            if (element.Count() > 0)

            {

                XElement firstelement = element.First();

                ///设置新的属性

                firstelement.SetAttributeValue("BookID", "new004");

                ///替换成新的节点

                firstelement.ReplaceNodes(

                        new XElement("BookNo", "new0004"),

                        new XElement("BookName", "Book new0004"),

                        new XElement("BookPrice", "45"),

                        new XElement("BookRemark", "This is a book new0004")

                    );

            }

            xe.Save(xmlpath);

            Console.WriteLine(xe);

        }

            //调用函数ModifyXmlElement(string xmlpath, string strElement)

            ///修改XML文件的元素

            Program.ModifyXmlElement(@"C:\BookStore.xml", "004");

        /// <summary>

        /// 4、删除XML文件的元素

        /// </summary>

        /// <param name="xmlpath">XML文件的路径</param>

        /// <param name="strElement">指定删除元素</param>

        private static void DeleteXmlElement(string xmlpath, string strElement)

        {

            XElement xe = XElement.Load(xmlpath);

            ///查询修改的元素

            IEnumerable<XElement> element = from e in xe.Elements("Book")

                                            where e.Attribute("BookID").Value == strElement

                                            select e;

            ///修改元素

            if (element.Count() > 0)

            {

                XElement firstelement = element.First();

                ///删除此元素的所有节点和属性

                firstelement.RemoveAll();

                ///删除此元素的属性

                //firstelement.RemoveAttributes();

                ///删除此元素的子节点

                //firstelement.RemoveNodes();

            }

            xe.Save(xmlpath);

            Console.WriteLine(xe);

        }

            //调用函数 DeleteXmlElement(string xmlpath, string strElement)

            ///删除XML元素

            Program.DeleteXmlElement(@"C:\BookStore.xml","new004");

        /// <summary>

        /// 5、将XML文件中的属性更换成元素

        /// </summary>

        /// <param name="xmlpath">XML文件的路径</param>

        /// <param name="strAttribute">指定要更换的属性</param>

        private static void ConvertAttributeToElement(string xmlpath, string strAttribute)

        {

            XElement xe = XElement.Load(xmlpath);

            ///查询更换的元素

            IEnumerable<XElement> element = from e in xe.Elements("Book")

                                            where e.Attribute("BookID").Value == strAttribute

                                            select e;

            ///更换为元素

            if (element.Count() > 0)

            {

                XElement firstelement = element.First();

                //获取第一个属性

                XAttribute attr = firstelement.FirstAttribute;

                //XAttribute attr = firstelement.Attribute("BookID");

                ///将属性转换成元素

                firstelement.AddFirst(

                    new XElement(attr.Name, attr.Value)//添加BookID元素

                    );

                ///删除属性

                firstelement.RemoveAttributes();

            }

            xe.Save(xmlpath);

            Console.WriteLine(xe);

        }

            //调用函数：ConvertAttributeToElement(string xmlpath, string strAttribute)

            ///删除XML元素

            //Program.DeleteXmlElement(@"C:\BookStore.xml","new004");//注释这一样



            ///将文件中的属性更换成元素

            Program.ConvertAttributeToElement(@"C:\BookStore.xml","new004");