private void ShowSell_Load(object sender, EventArgs e)
        {
            string    Error = "";
            DBProduct obj   = new DBProduct();
            DataTable table = obj.getAllSellsData(ref Error);

            if (Error != "")
            {
                MessageBox.Show(Error);
            }
            else
            {
                dataGridView1.DataSource = table;
            }
        }