private void frmNhanPhong_Load(object sender, EventArgs e)
{
lblPhong.Text = CurrentPhong.MaPH.ToString();
cbbKhachhang.DisplayMember = "HoTen";
cbbKhachhang.ValueMember = "MaKH";
cbbKhachhang.DataSource = _khDAL.GetTen();
dtpNgaynhan.Value = DateTime.Now;
}