private void txtProductDiscount_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                if (order.VERIFYQTY(txtProductID.Text, Convert.ToInt32(txtProductQTE.Text)).Rows.Count < 1)
                {
                    MessageBox.Show("الكميه المدخله لهذا المنتج غير متاحه", "اضافه الاصناف", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    return;
                }
                // this for check if this product found or not
                for (int i = 0; i < DGVNEWOrders.Rows.Count - 1; i++)
                {
                    if (DGVNEWOrders.Rows[i].Cells[0].Value.ToString() == txtProductID.Text)
                    {
                        MessageBox.Show("تم اضافه هذا الصنف من قبل", "اضافه الاصناف", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        return;
                    }
                }
                DataRow r = dt.NewRow();
                r[0] = txtProductID.Text;
                r[1] = txtProductName.Text;
                r[2] = txtProductPrice.Text;
                r[3] = txtProductQTE.Text;
                r[4] = txtProductQTEPrice.Text;
                r[5] = txtProductDiscount.Text;
                r[6] = txtProductTotal.Text;
                dt.Rows.Add(r);
                DGVNEWOrders.DataSource = dt;

                ClearBoxes();
                btnProductSearch.Focus();

                txtOrderSUM.Text = (from DataGridViewRow row in DGVNEWOrders.Rows where row.Cells[6].FormattedValue.ToString() != String.Empty select Convert.ToDouble(row.Cells[6].FormattedValue)).Sum().ToString();
            }
        }