List<T> 排序(Sort)查找(Find)功能的多种实现

时间：2011-03-31 来源：Aleax

记录 List<T>功能中的Sort和Find功能的几种实现方式

Person类

    public class Person:IComparable<Person>
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public Person(string name, int age)
        {
            this.Name = name;
            this.Age = age;
        }

        public int CompareTo(Person p)
        {
            return this.Age - p.Age;
        }

        public static int NameCompareTo(Person p1, Person p2)
        {
            return System.Collections.Comparer.Default.Compare(p1.Name, p2.Name);
        }
    }

调用类

List<Person> Persons = new List<Person>() {
                new Person("jdmin",20),
                new Person("aleax",35),
                new Person("xhina",23)
            };
            //排序
            //方法 1. 让Person类继承IComparable接口,实现CompareTo方法
            //Persons.Sort();
            //方法2.自定义一个方法来实现
            Persons.Sort(Person.NameCompareTo);
            //Persons.Sort(delegate(Person p1, Person p2) { return Comparer.Default.Compare(p2.Name, p1.Name); });
            foreach (Person p in Persons)
            {
                Console.WriteLine(p.Name + " Age:" + p.Age);
            }
            Console.WriteLine("------------------------------");
            //方法3. 使用Lambada
            //"Lambda表达式" 的语法格式：
            //参数列 => 语句或语句块
            //如果参数列中有0个或1个以上参数，则必须使用括号括住参数列
            var temList = Persons.OrderBy(p => p.Name);//名字升序, A-Z
            //var temList = Persons.OrderByDescending(p => p.Age);//按年龄降序
            foreach (Person p in temList)
            {
                Console.WriteLine(p.Name + " Age:" + p.Age);
            }
            Console.WriteLine("------------------------------");

            //查找年龄>25的数据
            //查找单个数据
            Person oPerson = Persons.Find(delegate(Person p) { return p.Name == "aleax"; });
            Console.WriteLine("Name: {0}, Age: {1}", oPerson.Name, oPerson.Age);
            //查找出满足条件的所有数据
            List<Person> ageList = Persons.FindAll(AgeFind);
            //var ageList = Persons.FindAll(delegate(Person p) { return p.Age > 25; });
            //var ageList = Persons.Where(p => p.Age > 25);
            foreach (Person p in ageList)
            {
                Console.WriteLine(p.Name + " Age:" + p.Age);
            }
            Console.WriteLine("------------------------------");
            //查看指定的名字是否存在
            var bUserExists=Persons.Exists(delegate(Person p){return p.Name=="aleax";});
            Console.WriteLine(bUserExists); 点击下载