private void LoadSoHopDong()
{
_KTCNHopDongRepo = new KTCNHopDongRepo();
cboSoHopDong.DisplayMember = "SO_HD";
cboSoHopDong.ValueMember = "SO_HD";
cboSoHopDong.DropDownColumns = "SO_HD,MA_TK";
cboSoHopDong.DataSource = _KTCNHopDongRepo.GetAll();
cboSoHopDong.SelectedIndex = -1;
}