asp.net Linq 实现分组查询

首先我们还是先建立一个person.cs类
public class person
    {
        public string name
        { get; set; }
        public int age
        { get; set; }
        public string 易做图
        { get; set; }
    }
接下来我们往这个person类添加数据：
List<person> plist1 = new List<person>();

plist1.Add(new person { name = "cxx1", age = 24, 易做图 = "男" });
plist1.Add(new person { name = "www.baidu.com", age = 25, 易做图 = "男" });
plist1.Add(new person { name = "www.52mvc.com", age = 26, 易做图 = "男" });

List<person> plist2 = new List<person>();

plist2.Add(new person { name = "cxx1", age = 24, 易做图 = "男" });
plist2.Add(new person { name = "cxx2", age = 28, 易做图 = "男" });
plist2.Add(new person { name = "cxx4", age = 27, 易做图 = "男" });
plist2.Add(new person { name = "cxx5", age = 28, 易做图 = "男" });
// asp.net
var query = from person p in plist1
     join person per in plist2
     on p.name equals per.name
     select new
     {
         名称=p.name,
         性别=p.易做图,
         年龄=p.age

     };
gd2.DataSource = query;
gd2.DataBind();

返回的结果是：

备注：这个方法是要查找出 plist1 与 plist2 之中，name名称有相同记录的数据。

接下来我们来看看sql中的左连接left join 在linq中如何实现
还是先来创建两个cs 类。

    /// <summary>
    /// 手机列表
    /// </summary>
    public class MobileStore
    {
        public string mobId
        { set; get; }
        public string mobName
        { set; get; }
    }
    /// <summary>
    /// 手机销售表
    /// </summary>
    public class MobileSale
    {
        public string Sid
        { set; get; }
        public string mobId
        { set; get; }
        public string mobName
        { set; get; }
        public string price
        { set; get; }
    }

List<MobileStore> listStore = new List<MobileStore>();

listStore.Add(new MobileStore { mobId = "1", mobName = "N86" });
listStore.Add(new MobileStore { mobId = "2", mobName = "N82" });
listStore.Add(new MobileStore { mobId = "3", mobName = "N81" });
listStore.Add(new MobileStore { mobId = "4", mobName = "N95" });
listStore.Add(new MobileStore { mobId = "5", mobName = "N85" });
listStore.Add(new MobileStore { mobId = "6", mobName = "N97" });

List<MobileSale> listSale = new List<MobileSale>();
listSale.Add(new MobileSale { Sid="1" ,mobId="1",mobName="N86",price="100"});
listSale.Add(new MobileSale { Sid="2", mobId = "2", mobName = "N82",price="220" });
listSale.Add(new MobileSale { Sid = "3", mobId = "3", mobName = "N81", price = "300" });

var query = from MobileStore m in listStore

            join MobileSale sale in listSale
            on m.mobId equals sale.mobId into joinm

            from j in joinm.DefaultIfEmpty()
            select new
            {
                ID = m.mobId,
                名称 = m.mobName,
                价格 = j == null ? "暂无数据" : j.price,
            };
gd.DataSource = query;
gd.DataBind();

补充：Web开发 , ASP.Net ,