protected void Button1_Click(object sender, EventArgs e)
 {
     if ((Boolean)Session["user"] == false)
     {
         Response.Redirect("login.aspx");
     }
     else
     {
         int?   idten = null;
         string ten   = Session["ten"].ToString();
         dt.lay(ten, ref idten);
         Txtnd.Text = (Txtnd.Text).Trim();
         dt.Binhluan_Insert(Txtnd.Text, Convert.ToInt32(Request["id"]), idten, DateTime.Now);
     }
 }