I want to add an order in my inventory management system by selecting a product from a datagridview.
This is my Products Grid view code :

int flag = 0;
private void ProductsGV_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
    product = ProductsGV.Rows[e.RowIndex].Cells[1].Value.ToString();
    uprice = Convert.ToInt32(ProductsGV.Rows[e.RowIndex].Cells[3].Value.ToString());
    flag = 1;
}

And This is my add button code :

private void button1_Click(object sender, EventArgs e)
        {
            if (QteTb.Text == "")
                MessageBox.Show("Entrez la quantité de produit");
            else if (flag == 0)
                MessageBox.Show("Choisir un produit");
            else
            {
                num = num + 1;
                qty = Convert.ToInt32(QteTb.Text);
                totprice = qty * uprice;
                DataTable table = new DataTable();
                //table.Columns.Add(num, product, qty, uprice, totprice);
                table.Rows.Add(num, product, qty, uprice, totprice);
                OrderGV.DataSource = table;
                //flag = 0;
            }
        }

When I try to add an order I get This error : “The input table is longer than the number of columns in this table.”