private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox2.Text != "")
{
string maHH = comboBox2.SelectedValue.ToString();
DataTable dt = HangHoaBLL.LayDuLieuChoTB(maHH);
tbTHH.Text = dt.Rows[0][1].ToString();
tbDVT.Text = dt.Rows[0][2].ToString();
DonGia.Text = dt.Rows[0][3].ToString();
}
else
{
tbTHH.Text = "";
tbDVT.Text = "";
DonGia.Text = "";
}
}