private void btnThemDonViTinh2_Click(object sender, EventArgs e)
        {
            FrmDanhSachDVT frm = new FrmDanhSachDVT();

            frm.ShowDialog();
        }
        private void btnThemNhaCungCap_Click(object sender, EventArgs e)
        {
            FrmDanhSachDVT frm = new FrmDanhSachDVT();

            frm.ShowDialog();
        }