private void cmdThemHoaDon_Click(object sender, RoutedEventArgs e)
 {
     frmHoaDonDichVuEdit HoaDonDichVuEdit = new frmHoaDonDichVuEdit();
     HoaDonDichVuEdit.Closed += new EventHandler(HoaDonDichVuEdit_Closed);
     HoaDonDichVuEdit.HoaDonDichVu_Load(0);
     HoaDonDichVuEdit.Show();
 }
 private void cmdSuaHoaDon_Click(object sender, RoutedEventArgs e)
 {
     HyperlinkButton cmdSuaHoaDon = sender as HyperlinkButton;
     int HoaDonDichVuID = int.Parse(cmdSuaHoaDon.CommandParameter.ToString());
     frmHoaDonDichVuEdit HoaDonDichVuEdit = new frmHoaDonDichVuEdit();
     HoaDonDichVuEdit.Closed += new EventHandler(HoaDonDichVuEdit_Closed);
     HoaDonDichVuEdit.HoaDonDichVu_Load(HoaDonDichVuID);
     HoaDonDichVuEdit.Show();
 }