private void button5_Click(object sender, EventArgs e) { if (textBox7.Text != null) { clsOrder order = new clsOrder(); var data = Convert.ToInt32(textBox7.Text); if (order.findOne(data)) { listBox1.Items.Clear(); listBox1.Items.Add(order.Product_Id.ToString() + " - " + order.Product_Name + " - " + order.Date_Ordered); } else { MessageBox.Show("Data not found."); } } else { MessageBox.Show("Please enter a number into the find field."); } }