C# LINQ 中關於from和select的一個小例子

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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace First_exam{    class Student    {        /// <summary>        ///學生姓名的欄位和屬性        /// </summary>        private string _Name;        public string Name        {            get { return this._Name; }        }        private string _Xingbie;        /// <summary>        /// 學生性別的欄位和屬性        /// </summary>        public string Xingbie        {            get { return this._Xingbie; }        }        /// <summary>        /// 學生年齡的欄位和屬性        /// </summary>        private uint _Age;        public uint Age        {            get { return this._Age; }        }        /// <summary>        /// 學產生績的欄位和屬性        /// </summary>        private List<LessonScore> _Scores;        public List<LessonScore> Scores        {            get { return this._Scores; }        }        /// <summary>        /// 建構函式，傳入學生姓名，性別，年齡，成績        /// </summary>        public Student(string name, string xb, uint age, List<LessonScore> scrs)        {            this._Name = name;            this._Xingbie = xb;            this._Age = age;            this._Scores = scrs;        }        public Student(string name, string xb, uint age)        {            this._Name = name;            this._Xingbie = xb;            this._Age = age;            this._Scores = null;        }        public override string ToString()        {            string str;            str = string.Format("{0}--{1}--{2}",this._Name, this._Age,this._Xingbie);            return str;        }    }    class LessonScore    {        /// <summary>        /// 課程成績的欄位和屬性        /// </summary>        private float _Score;        public float Score        {            get { return this._Score; }        }        /// <summary>        /// 課程名稱的欄位和屬性        /// </summary>        private string _Lessson;        public string Lesson        {            get { return this._Lessson; }        }        /// <summary>        /// 建構函式        /// </summary>        public LessonScore(string les, float scr)        {            this._Lessson = les;            this._Score = scr;        }        public override string ToString()        {            string str;            str = string.Format("{0}----{1}分", this._Lessson,this._Score);            return str;        }    }    class Program    {        static void Main(string[] args)        {            Student[] arr =             {                new Student("張氏那","男",20),                new Student("李四","男",23),                new Student("李霞","女",21),                new Student("王媽媽","女",29),                new Student("郭明","男",22),                new Student("歐陽夏","女",24),                new Student("王丹","女",20),                new Student("張寶","男",25),            };            var query =                from val in arr                select val;            foreach (Student item in query)            {                Console.WriteLine(item);            }            Console.WriteLine();            var query2 =                from val in arr                select val.Name;            foreach(string item in query2)            {                Console.Write("{0},   ",item);            }            Console.WriteLine();            Console.WriteLine();            var query3 =                from val in arr                select val.Name.Length;            foreach (int item in query3)            {                Console.Write("{0},   ", item);            }            Console.WriteLine();            Console.WriteLine();            var query4 =                from val in arr                select new { val.Name, val.Age,  NameLen = val.Name.Length};            foreach(var item2 in query4)            {                Console.WriteLine(item2);            }                               }    }}

 

C# LINQ 中關於from和select的一個小例子