private void button2_Click(object sender, EventArgs e) { var store = new Store(); var fin = new Finance(); string datatable = Interaction.InputBox("Input How much tables do you want to sell", "Order", "0"); int tables = Int32.Parse(datatable.Trim()); store.SaleTable(tables); fin.SaleProduct(tables); textBox2.Text = store.TableNum.ToString(); using (StreamReader sr = new StreamReader(fin.moneypath, Encoding.Default)) { textBox3.Text = sr.ReadLine(); } }