BoyLee's Blog

//实体,为了oo,将关系型数据库转化为实体对象
[Table (Name="Post")]
public class PostInfo
{
    [Column(Name = "uid")] public int uid { get; set; }
    [Column(Name = "pid")] public int pid { get; set; }
    [Column(Name = "p_content")] public string p_content { get; set; }
}

public class UserInfo
{
    //更方便的属性访问器,自动实现属性
    public int uid {get;set;}
    public string username {get;set;}
    public string password {get;set;}
    public string intro {get;set;}
}

//隐式类型本地变量
var test="First Test";
Response.Write(test);
//对象和集合初始值设定项
var list = new List<string>() { "<br/>", "LinQ ", "を ", "よく ", "勉強したいです。", "<br/>" };
foreach (var tmp in list) Response.Write(tmp);
var user = new UserInfo{uid=1,username="Lee",intro="Just Test"};
Response.Write("ID:" + user.uid + "<br/>" + "名前:" + user.username + "<br/>");
//对象和集合初始值设定项
var userlist = new[]
{
    new UserInfo{uid=2,username="zhang",intro="hi"},
    new UserInfo{uid=3,username="wang",intro="test"},
    new UserInfo{uid=4,username="chen",intro="linq"},
};
foreach (var tmp in userlist) Response.Write("ID:" + tmp.uid + "<br/>" + "名前:" + tmp.username + "<br/>");
//匿名类型
var tmpuserlist = from u in userlist
    where u.uid >= 3
    select new { uid=u.uid,username=u.username,intro=u.intro };
foreach (var tmp in tmpuserlist) Response.Write("ID:" + tmp.uid + "<br/>" + "名前:" + tmp.username + "<br/>");

//DataContext连接数据库
DataContext dc = new DataContext(@"F:\wwwroot\LinqTest\Data\LinqTest.mdf");
//GetTable取得数据库中的表
Table<PostInfo> tblPost = dc.GetTable<PostInfo>();
Table<CommentInfo> tblComment = dc.GetTable<CommentInfo>();
//查询综合
var tmpResult = from p in tblPost
    from c in tblComment
    where p.pid==c.pid
    orderby p.pid
    select new{pid=p.pid,cid=c.cid,content=p.p_content};
foreach(var item in tmpResult) Response.Write(" CommentID:" + item.cid + " Content:" + item.content + "<br/>");