private void cMnu_Add_Click(object sender, EventArgs e)
        {
            FrmProductMaster frm = new FrmProductMaster();

            frm.ForSelect = true;
            if (frm.ShowDialog() == DialogResult.OK)
            {
                Product p = frm.SelectedItem as Product;
                AddPurchaseSheettem(p);
            }
        }
        private void lnkProduct_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            FrmProductMaster frm = new FrmProductMaster();

            frm.ForSelect = true;
            if (frm.ShowDialog() == DialogResult.OK)
            {
                Product           = frm.SelectedItem as Product;
                txtProductID.Text = Product != null ? Product.Name : string.Empty;
            }
        }