protected void Page_Load(object sender, EventArgs e)
 {
     if (!IsPostBack)
     {
         HiddenField1.Value = (string)Session["uname"];
         if (HiddenField1.Value != (string)Session["uname"])
         {
             Response.Redirect("log.aspx");
         }
         DropDownList1.DataSource     = d1.getairport();
         DropDownList1.DataTextField  = "name";
         DropDownList1.DataValueField = "id";
         DropDownList1.DataBind();
     }
 }