private void frmQLPhong_Load(object sender, EventArgs e)
{
cbMaToaNha.SelectedIndex = 0;
cbLoaiPhong.SelectedIndex = 0;
cbTimKiem.SelectedIndex = 0;
dgQLPhong.DataSource = PHBLL.Load();
btSua.Enabled = false;
btXoa.Enabled = false;
}