Linq初探

1.添加Live.dbml文件。

 

2.LiveDataContext ctx = new LiveDataContext();

 

3.dl_list.DataSource = from live in ctx.HQB_Live_Main orderby live.id descending select live;

 

4.var articles = ldc.HQB_LiveInfo_Main.OrderByDescending(p => p.id).Skip(StartRecord).Take(PageSize);

   dl_list.DataSource = articles;
   dl_list.DataBind();

 

5.dl_list.DataSource = ctx.HQB_Live_Main;

 

6.ctx.HQB_Live_Main.InsertOnSubmit(live);

   ctx.SubmitChanges(); //插入数据。

 

//更新数据，方法一

 // 

var user = context.Users.Single(u => u.UserName == "Jone");

user.UserEmail = "Jone@123.com";

context.SubmitChanges();

//更新数据，方法二

// 

            

var query1 = (from q in context.Users where q.UserName == "Jone" select q).SingleOrDefault();

//判断query1是否为空，若不为空，则修改UserEmail。

 if (query1 != null)

 {

    query1.UserEmail = "Tom@sina.com";

     context.SubmitChanges();

 }

 

//删除数据

var user = from u in context.Users where u.UserEmail == "xyzqiang@163.com" select u;

context.Users.DeleteAllOnSubmit(user);

context.SubmitChanges();

 

 

 

//用户登录方法

public int User_Login(string uid, string pwd)
  {
        var r = from d in dcu.ZQ_Users where d.Uid == uid && d.Pwd == pwd select d;

        if (r.Count() > 0)
        {
            return 1;
        }
        else
        {
            return 0;
        }

}