linq实例 - Group的使用

 新建用户类：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsFormsApplication1
{
    class user
    {
        private string firstName;
        private string lastName;

        public string FirstName
        {
            get { return this.firstName; }
            private set { }
        }

        public string LastName
        {
            get { return this.lastName; }
            private set { }
        }

        public user(string firstName, string lastName)
        {
            this.firstName = firstName;
            this.lastName = lastName;
        }

    }
}

 

使用LInq

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //准备数据
            user[] users = new user[3];
            users[0] = new user("zhou", "min");
            users[1] = new user("zhang", "li");
            users[2] = new user("zhou", "lei");
            var newUsers = from u in users group u by u.FirstName into usergroup select usergroup;
            foreach (var a in newUsers) //a是group来的。可能包含不止一个记录。  
            { 
                foreach(user b in a) //再次循环，把a包含的循环拿出来。这里的b是user对象了。  
                    MessageBox.Show(String.Format("{0},{1}",b.LastName, b.FirstName));  
            } 

        }
    }
}