Linq to XML增删改查

直接上示例：

XML文件：

<?xml version="1.0" encoding="utf-8"?>
<users>
  <user id="001">
    <name>Xi</name>
    <age>24</age>
    <sale>male</sale>
    <address>Haidian</address>
  </user>
</users>

User实体类：

    public class User
    {
        public string ID { get; set; }
        public string Name { get; set; }
        public string Age { get; set; }
        public string Sale { get; set; }
        public string Address { get; set; }
    }

XML文件操作：

        #region Operate the xml file

        public void ConnectToXmml()
        {
            if (!File.Exists(path))
            {
                XElement Users = new XElement("users", "");
                Users.Save(path);
            }
        }

        public bool AddToXml(User user)
        {
            XElement Users = XElement.Load(path);
            XElement newUser = new XElement("user",
                new XAttribute("id", user.ID),
                new XElement("name", user.Name),
                new XElement("age", user.Age),
                new XElement("sale", user.Sale),
                new XElement("address", user.Address)
                );
            var u = Users.Elements("user").Where(uu => uu.Attribute("id").Value == user.ID);
            if (u.Count() > 0)
                return false;
            else
            {
                Users.Add(newUser);
                Users.Save(path);
                return true;                
            }

        }

        public bool UpdateToXml(User user)
        {
            XElement Users = XElement.Load(path);
            var uu = Users.Elements("user").Where(u => u.Attribute("id").Value == user.ID);
            if (uu.Count() > 0)
            {
                XElement newUser = uu.First();
                newUser.ReplaceNodes(
                    new XElement("name", user.Name),
                    new XElement("age", user.Age),
                    new XElement("sale", user.Sale),
                    new XElement("address", user.Address)
                    );
                Users.Save(path);
                return true;                
            }
            else
                return false;
        }

        public bool DeleteFromXml(string ID)
        {
            XElement Users = XElement.Load(path);
            var uu = Users.Elements("user").Where(u => u.Attribute("id").Value == ID);
            if (uu.Count() > 0)
            {
                uu.Remove();
                Users.Save(path);
                return true;                
            }
            else
                return false;

        }

        public User Queryuser(string ID)
        {
            User newUser = null;
            XElement Users = XElement.Load(path);
            var uu = Users.Elements("user").Where(u => u.Attribute("id").Value == ID);
            if (uu.Count() > 0)
            {
                XElement xUser = uu.First();
                newUser = new User
                {
                    ID = ID,
                    Name = xUser.Element("name").Value,
                    Age = xUser.Element("age").Value,
                    Sale = xUser.Element("sale").Value,
                    Address = xUser.Element("address").Value,
                };
            }
            return newUser;
        }

        #endregion