List<T> 的扩展方法

  //List<T>.Take(m)      //取出 前m行         

    IEnumerable<Person> takeList = lstPerson.Take(4);      

       foreach (Person s in takeList) { Console.WriteLine("element in takeList: " + s); }

            //List<T>.Where()            

  Console.WriteLine("找出Name='puma'的Person ");    

         IEnumerable<Person> whereList = lstPerson.Where(name => { if (name.Name == "puma") { return true; } else { return false; } });       

      Console.WriteLine(lstPerson.Where(name => { if (name.Name == "puma") { return true; } else { return false; } }));     

        foreach (Person s in lstPerson) { Console.WriteLine("element in subList: " + s); }    

         //List<T>.Find()              //找出Name='puma'的Person        

      Console.WriteLine("找出Name='puma'的Person→ ");         

    Console.WriteLine(lstPerson.Find(delegate (Person p) { return p.Name == "puma"; }).ToString() + "<p>");

            //List<T>.FindAll()              //找出Age>10的數目     

         Console.WriteLine("找出Age>10的數目→ ");   

          Console.WriteLine(lstPerson.FindAll(delegate (Person p) { return p.Age > 10; }).Count.ToString() + "<p>");    

         //List<T>.Exists()              //檢查Name='F6'是否存在       

       Console.WriteLine("檢查Name='F6'是否存在→ ");         

    Console.WriteLine(lstPerson.Exists(delegate (Person p) { return p.Name == "F6"; }).ToString() + "<p>");         

    //依Name升冪排序 

            Console.WriteLine("<p>依Name升冪排序↑<br/>");

            lstPerson.Sort(delegate (Person p1, Person p2) { return Comparer<string>.Default.Compare(p1.Name, p2.Name); });

            foreach (Person p in lstPerson)             {                 Console.WriteLine(p.ToString() + "<br/>");             }     

        //List<T>.Sort()              //依Name降冪排序           

   Console.WriteLine("<p>依Name降冪排序↓<br/>");

            lstPerson.Sort(delegate (Person p1, Person p2) { return Comparer<string>.Default.Compare(p2.Name, p1.Name); });

            foreach (Person p in lstPerson)             {                 Console.WriteLine(p.ToString() + "<br/>");             }

 public class Person     {         private int _ID;         private string _Name;         private int _Age;

        public Person(int ID, string Name, int Age)         {             _ID = ID;             _Name = Name;             _Age = Age;         }

        public int ID         {             set { _ID = value; }             get { return _ID; }         }         public string Name         {             set { _Name = value; }             get { return _Name; }         }         public int Age         {             set { _Age = value; }             get { return _Age; }         }

        public override string ToString()         {             return string.Format("ID：{0}，Name：{1}，Age：{2}", _ID, _Name, _Age);         }

    }