XML文件的简单读，写，创建

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Xml;
using System.IO;
using System.Data;

namespace VS_CSharp2008_WinForm_Orders0716
{
    class LoadXML
    {
        public void XML_Init()
        {
            //if (!File.Exists(@"XML/myconf.xml")) { CreateXmlFile(@"XML/myconf.xml", "MyConfig"); }
            //if (!File.Exists(@"XML/user.xml")) { CreateXmlFile(@"XML/user.xml", "User"); CreateDefaultUser(); }
            //LoadUser loadUser = new LoadUser();
            //loadUser.USER_Init();

            // loading myconf.xml
            // 条件删除节点
            XmlDocument xmldoc = new XmlDocument();
            xmldoc.Load(@"XML/myconf.xml");
            foreach (XmlNode p in xmldoc.DocumentElement.ChildNodes)
            {
                //Console.WriteLine(xmldoc.DocumentElement.ChildNodes.Count);

                foreach (XmlNode p1 in p.ChildNodes)
                {
                    //Console.WriteLine(xmldoc.DocumentElement.ChildNodes.Count);

                    Console.WriteLine(p1.ChildNodes[0].Value);
                    if (p1.ChildNodes[0].Value == "adfs")
                    {
                        xmldoc.DocumentElement.RemoveChild(p1.ParentNode);
                        xmldoc.Save(@"XML/myconf.xml");
                        break;
                    }
                }

            }
        }

        private void CreateXmlFile(string strFilePath, string strRootElement)
        {
            // 方法一：
            // XmlTextWriter.Create(strFilePath);

            // 方法二：
            // 创建xmldoc
            XmlDocument xmldoc = new XmlDocument();
            XmlDeclaration xmldecl = xmldoc.CreateXmlDeclaration("1.0", Encoding.Unicode.EncodingName, null);
            xmldoc.AppendChild(xmldecl);
            // 加入根元素
            XmlElement rootElement = xmldoc.CreateElement(strRootElement);
            xmldoc.AppendChild(rootElement);
            // 加入根的子节点
            //XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.Element, "price", null);
            //xmlnode.InnerText = "19.95";
            //xmldoc.DocumentElement.AppendChild(xmlnode); 
            // 保存
            xmldoc.Save(strFilePath);
        }

        private void CreateDefaultUser()
        {
            string[] accountName = new string[] { "Admin", "User", "Guest" };
            XmlDocument xmldoc = new XmlDocument();
            xmldoc.Load(@"XML/user.xml");

            for (int i = 0; i < accountName.Length; i++)
            {
                XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.Element, "account" + i, null);
                xmlnode.InnerText = accountName[i];

                XmlAttribute xmlattr = xmldoc.CreateAttribute("pwd");
                xmlattr.Value = Encrypt(accountName[i]);

                xmldoc.DocumentElement.AppendChild(xmlnode);

                xmldoc.DocumentElement["account" + i].SetAttributeNode(xmlattr);
            }
            xmldoc.Save(@"XML/user.xml");
        }

        private string Encrypt(string strEncrypt)
        {
            string EncryptString = string.Empty;
            System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
            byte[] md5_s = md5.ComputeHash(System.Text.Encoding.Unicode.GetBytes(strEncrypt));
            for (int i = 0; i < md5_s.Length; i++)
            {
                EncryptString = EncryptString + md5_s[i].ToString("X");
            }
            return EncryptString;
        }
    }

    class LoadUser
    {
        public DataTable userTable;

        public void USER_Init()
        {
            userTable = new DataTable();

            XmlTextReader xmlTextReader1 = new XmlTextReader(@"XML/user.xml");
            xmlTextReader1.Read();
            while (xmlTextReader1.Read())
            {
                if (xmlTextReader1.Value == "Admin")
                {
                    System.Windows.Forms.MessageBox.Show(xmlTextReader1.Value.ToString());
                    break;
                }
            }
        }
    }
}