private void LoadLoaiNguoiDung()
{
NguoiDungBLL nguoiDungBLL = new NguoiDungBLL();
lkup_LoaiNguoiDung.DataSource = nguoiDungBLL.LayLoaiNguoiDung();
lkup_LoaiNguoiDung.ValueMember = "ID_Loai_Nguoi_Dung";
lkup_LoaiNguoiDung.DisplayMember = "Loai_ND";
}