linq多表查询

        protected void Page_Load(object sender, EventArgs e)
        {
            //Response.Write(JsonConvert.SerializeObject(new { name = "Eric", info = new { age = 20, address = "襄阳" } }));

            //linq查询语法：单表查询
            //using (StudentDBDataContext db = new StudentDBDataContext())
            //{
            //    var query = from c in db.Stu
            //                join s in db.Class
            //                on c.Cid equals s.Cid
            //                select new { c.Name, s.Cname };
            //    Response.Write(JsonConvert.SerializeObject(query));
            //}

            //linq查询语法：两表查询
            //using (StudentDBDataContext db = new StudentDBDataContext())
            //{
            //    var query = from l in db.Lesson
            //                join s in db.SCType
            //                on l.sid equals s.sid
            //                select new
            //                {
            //                    l.Lid,
            //                    l.Lname,
            //                    l.LTime,
            //                    l.Laddress,
            //                    l.LstTime,
            //                    l.LclTime,
            //                    l.Teacher,
            //                    l.limitNum,
            //                    l.actualNum,
            //                    s.TName
            //                };
            //    Response.Write(JsonConvert.SerializeObject(query));
            //}

            //linq方法语法：两表查询
            //using (StudentDBDataContext db = new StudentDBDataContext())
            //{
            //    var query = db.Lesson.Join(
            //        db.SCType,
            //        l => l.sid, s => s.sid,
            //        (l, s) => new
            //        {
            //            l.Lid,
            //            l.Lname,
            //            l.LTime,
            //            l.Laddress,
            //            l.LstTime,
            //            l.LclTime,
            //            l.Teacher,
            //            l.limitNum,
            //            l.actualNum,
            //            s.TName
            //        }).ToList();
            //    Response.Write(JsonConvert.SerializeObject(query));
            //}

            //linq方法语法：两表查询
            //using (StudentDBDataContext db = new StudentDBDataContext())
            //{
            //    var query = from c in db.Class
            //                join s in db.Stu
            //                on c.Cid equals s.Cid
            //                select new
            //                {
            //                    c.Cid,
            //                    c.Cname,
            //                    c.Ccode,
            //                    s.Name,
            //                    s.Num,
            //                    s.Pwd
            //                };
            //    Response.Write(JsonConvert.SerializeObject(query));
            //    gv.DataSource = query;
            //    gv.DataBind();
            //}

            //linq方法语法：两表查询
            //using (StudentDBDataContext db = new StudentDBDataContext())
            //{
            //    var query = db.Stu.Join(db.Class, a => a.Cid, b => b.Cid, (a, b) => new { a.Cid, a.Name, b.Cname }).ToList();
            //    Response.Write(JsonConvert.SerializeObject(query));
            //    gv.DataSource = query;
            //    gv.DataBind();
            //}

            //var query = new TestClass().QueryLesson();
            //var json = JsonConvert.SerializeObject(query);
            //Response.Write(query);
            //gv.DataSource = query;
            //gv.DataBind();

            //linq方法语法：两表查询
            //using (StuDBEntities db = new StuDBEntities())
            //{
            //    var query = db.Lesson.Join(
            //    db.SCType,
            //    l => l.sid, s => s.sid,
            //    (l, s) => new
            //    {
            //        l.Lid,
            //        l.Lname,
            //        l.LTime,
            //        l.Laddress,
            //        l.LstTime,
            //        l.LclTime,
            //        l.Teacher,
            //        l.limitNum,
            //        l.actualNum,
            //        s.TName
            //    }).ToList();
            //    Response.Write(JsonConvert.SerializeObject(query));
            //    gv.DataSource = query;
            //    gv.DataBind();
            //}

            //linq方法语法：三表查询
            //using (StuDBEntities db = new StuDBEntities())
            //{
            //    var name = "w";
            //    var query = db.Stu.Join(db.Lesson, s => s.Lid, l => l.Lid,
            //        (s, l) => new
            //        {
            //            s.Name,
            //            s.Pwd,
            //            l.Lname,
            //            l.sid
            //        }).Join(db.SCType, a => a.sid, t => t.sid,
            //        (a, t) => new
            //        {
            //            a.Name,
            //            a.Pwd,
            //            a.Lname,
            //            t.TName
            //        }).Where(a => a.Name.Contains(name)).ToList();
            //    Response.Write(JsonConvert.SerializeObject(query));
            //    gv.DataSource = query;
            //    gv.DataBind();
            //}
        }