linq to xml

一      private static string name, num;

        public static string Num
        {
            get { return SysConfig.num; }
            set { SysConfig.num = value; }
        }

        public static string Name
        {
            get { return SysConfig.name; }
            set { SysConfig.name = value; }
        }        
        public static void CreateXML(string filepath)                
        {
           StudentDataContext studc = new StudentDataContext();
           var stu = from s in studc.Student
                      select s;

            XElement stuxml = new XElement("Students");
            foreach (Student s in stu)
            {
                stuxml.Add(new XElement("student",
                           new XAttribute("Name", s.StuName),
                           new XElement("Number", s.StuNum)));
            }
            stuxml.Save(filepath);
        }
      
       
        public static  XDocument doc;

        public static void ReadDefaultValue(string filepath) 
        {
            // 有很多student标签，默认为第一个
            try
            {
                doc = XDocument.Load(filepath);
                num = doc.Element("Students").Element("student").Value;
                name = doc.Element("Students").Element("student").Attribute("Name").Value;
            }
            catch
            {
                // 如果try里有错，也不影响运行
                num = "100000";
                name = "xy";
            }
        }

        public static IEnumerable<XElement> Find(string filepath)
        {
             doc = XDocument.Load(filepath);
             var result = from r in doc.Element("Students").Elements("student")
                          where (string)r.Attribute("Name").Value == "xy"
                          select r;
            return result;
        }

        public static void Remove(string filepath)
        {
            doc = XDocument.Load(filepath);
            doc.Element("Students").Elements("student").Where(ss => ss.Attribute

           ("Name").Value.ToString() == "xy").Remove();
            doc.Save(filepath);
        }

        public static void Add(string filepath)
        {
            doc = XDocument.Load(filepath);
            doc.Element("Students").Add(new XElement("student",
                                        new XAttribute("Name", "小明"),
                                        new XElement("Number", "111")));
            doc.Save(filepath);
        }

        public static void SetValue(string filepath)
        {
            doc = XDocument.Load(filepath);
            doc.Element("Students").Elements("student").Where(ee => (string)ee.Attribute("Name")

             == "xy").FirstOrDefault().SetAttributeValue("Name", "xy");
            doc.Element("Students").Elements("student").Where(ee => (string)ee.Attribute("Name")

            == "xy").FirstOrDefault().SetElementValue("Number", "100000");
            doc.Save(filepath);
         }
    }

二.

public static class BlackWhite
    {
        //private static string FindConfigFile(string fileName)
        //{
        //    //return HttpContext.Current.Server.MapPath(string.Format("~/Config/{0}",

              fileName));  // 找到XML文件路径
        //}

        private static IEnumerable<string> Black;
       
        public static IEnumerable<string> Black1
        {
            get { return BlackWhite.Black; }
            set { BlackWhite.Black = value; }
        }

        private static IEnumerable<string> White;
       
        public static IEnumerable<string> White1
        {
          get { return BlackWhite.White; }
          set { BlackWhite.White = value; }
        }

        public static void UseXml()
        {
            //XDocument doc = XDocument.Load(FindConfigFile("BlackWhite.xml"));
            string str = System.Environment.CurrentDirectory;
            XDocument doc = XDocument.Load(string.Format(@"{0}\BlackWhite.xml", str));
            Black = doc.Element("List").Element("Black").Elements("Name").Select(element =>

                    element.Value);
            White = doc.Element("List").Element("White").Elements("Name").Select(element =>

                    element.Value);
            Process[] processes = Process.GetProcesses();
            foreach (Process p in processes)
            {
                if (Black.Contains(p.ProcessName))
                {
                    p.Kill();
                    MessageBox.Show("上课请不要打开无关程序");
                   
                }
            }
         
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<List>
  <Black>
   <Name>QQ</Name>
   <Name>AliIm</Name>
  </Black>
   <White>
     <Name>SeverUDP</Name>
     <Name>ClientUDP</Name>
   </White>
</List>