/// <summary>
/// webform databae first
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Button1_Click(object sender, EventArgs e)
{
studentttEntities content = new studentttEntities();
var query = from a in content.Set <studnet>().AsNoTracking()
join b in content.Set <city>().AsNoTracking() on a.cityid equals b.cityid
join c in content.Set <hobby>().AsNoTracking() on a.hobbyid equals c.hobbyid
where a.stuname == TextBox1.Text
select new
{
a.stuname,
b.cityname,
c.hobbyname
};
string sql = query.ToString();
Label1.Text = sql;
GridView1.DataSource = query.ToList();
GridView1.DataBind();
}
protected void Button1_Click(object sender, EventArgs e)
{
studentttEntities content = new studentttEntities();
///linq 表达式 查询
var students1 = from t in content.Set <studnet>().AsNoTracking()
where t.stuname == "hans"
select new { t.stuname, t.hobbyid, t.cityid };
///tolist 去 数据库 执行
var query1 = students1.ToList();
GridView1.DataSource = query1;
GridView1.DataBind();
///lambda 表达式查询
var students2 = content.studnet.Where(t => t.stuname == "hans")
.Select(t => new { t.stuname, t.hobbyid, t.cityid });
var query2 = students2.ToList();
GridView2.DataSource = query2;
GridView2.DataBind();
}