protected void Button1_Click(object sender, EventArgs e)
 {
     DataTable d2 = d1.getdepart(DropDownList1.SelectedValue);
     {
         if (d2.Rows.Count > 0)
         {
             GridView1.DataSource = d1.getdepart(DropDownList1.SelectedValue);
             GridView1.DataBind();
         }
         else
         {
             Response.Write("<script>alert('No data found on this airport! Select another')</script>");
         }
     }
 }