using System;

using System.Data;

using System.Configuration;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Text;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Collections.Generic;

using System.Collections;

　　#region 用Count()得出查询结果的个数

   Response.Write("<hr>用Count()得出查询结果的个数<br>");

   var langCount = (from s in GetStudents() select s.Language).Distinct().Count();

   Response.Write(string.Format("<div class='result'>{0}</div>", langCount));

   #endregion

   #region 用Count()的Lambda表达式满足条件的元素个数

   Response.Write("<hr>用Count()得出查询结果的个数<br>");

   var ageCoun = (from s in GetStudents() select s.Age).Count(a => a>);

   Response.Write(string.Format("<div class='result'>{0}</div>", ageCoun));

   #endregion

    #region 用Sum()将查询结果相加

   Response.Write("<hr>用Sum()将查询结果相加<br>");

    var ageSum = (from s in GetStudents() select s.Age).Sum();

    //var ageSum = GetStudents().Sum(s => s.Age);

    Response.Write(string.Format("<div class='result'>{0}</div>", ageSum));

    #endregion

    #region 用Min()得出查询结果的最小值

   Response.Write("<hr>用Min()得出查询结果的最小值<br>");

    var ageMin = (from s in GetStudents() select s.Age).Min();

    //var ageMin = GetStudents().Min(s => s.Age);

    Response.Write(string.Format("<div class='result'>{0}</div>", ageMin));

    #endregion

    #region 用Max()得出查询结果的最大值

   Response.Write("<hr>用Max()得出查询结果的最大值<br>");

    var ageMax = (from s in GetStudents() select s.Age) .Max();

    //var ageMax = GetStudents().Max(s => s.Age);

    Response.Write(string.Format("<div class='result'>{0}</div>", ageMax));

    #endregion

    #region 用Average()得出查询结果的平均值

   Response.Write("<hr>用Average()得出查询结果的平均值<br>");

    var ageAverage = (from s in GetStudents() select s.Age) .Average();

    //var ageAverage = GetStudents().Average(s => s.Age);

    Response.Write(string.Format("<div class='result'>{0}</div>", ageAverage));

    #endregion 

#region 构造一个学生集合体

private List<Student> GetStudents()

{

    List<Student> students = new List<Student>

    {

        new Student

        {

            Name="YOUNG",

            Age=,

            Language="Chinese"

        },

        new Student

        {

            Name="JESSIE",

            Age=,

            Language="Scotland"

        },

        new Student

        {

            Name="KELLY",

            Age=,

            Language="English"

        },

        new Student

        {

            Name="JUNE",

            Age=,

            Language="English"

        }

    };

    return students;

}

#endregion

#region 学生类

class Student

{

    public int Age { get; set; }

    public string Name { get; set; }

    public string Language { get; set; }

}

#endregion