private void UserControl3_1_Load(object sender, EventArgs e)
{
txtTenNhanVien.Enabled = false;
txtSoLan.Enabled = false;
for (int i = 0; i < bus.getMaNV().Rows.Count; i++)
{
cbbNhanVien.Items.Add(bus.getMaNV().Rows[i]["MANV"].ToString() + " - " + bus.getMaNV().Rows[i]["TENNV"].ToString());
cbb[i] = bus.getMaNV().Rows[i]["MANV"].ToString();
}
}